阅读说明：本技术 确定细胞样品中靶核酸存在或不存在的方法 (Method for determining the presence or absence of a target nucleic acid in a cell sample ) 是由 M·斯普林格-豪瑟斯 C·库普弗 P·沙茨 于 2013-08-16 设计创作，主要内容包括：确定细胞样品中靶核酸存在或不存在的方法,所述方法包括：a)将含有阴离子交换部分的表面与样品在适合诱导所述细胞和表面之间结合的条件下接触；b)将结合有细胞的表面与剩余样品分离以收集细胞；c)从细胞释放核酸；d)在靶核酸和靶核酸的特异性探针之间形成杂交体；和e)检测所述杂交体的存在或不存在。本发明提供快速和可自动化的方法,其中通过与阴离子交换表面的结合从周围的液体介质,如液基细胞学介质细胞收集细胞,如源自子宫颈拭子样品的上皮细胞。细胞以高亲和力和快速动力学特征直接结合于优选由携带阴离子交换部分的磁性颗粒提供的阴离子交换表面。结合于阴离子交换表面的细胞易与周围介质分离,可以直接重悬于适合在步骤d)中进行的后续杂交体捕获测定的组合物以检测,例如病原体核酸,如HPV核酸。(A method of determining the presence or absence of a target nucleic acid in a cell sample, the method comprising: a) contacting a surface comprising an anion exchange moiety with a sample under conditions suitable to induce binding between the cell and the surface; b) separating the cell-bound surface from the remaining sample to collect cells; c) releasing the nucleic acid from the cell; d) forming a hybrid between the target nucleic acid and the probe specific for the target nucleic acid; and e) detecting the presence or absence of the hybrid. The present invention provides a rapid and automatable method wherein cells, such as epithelial cells derived from a cervical swab sample, are collected from surrounding liquid medium, such as liquid-based cytological medium cells, by binding to an anion exchange surface. Cells bind directly with high affinity and fast kinetic characteristics to the anion exchange surface preferably provided by the magnetic particles carrying the anion exchange moiety. The cells bound to the anion exchange surface are easily separated from the surrounding medium and can be directly resuspended in a composition suitable for the subsequent hybrid capture assay performed in step d) for detection of, for example, pathogen nucleic acids, such as HPV nucleic acids.)

1. A method of determining the presence or absence of a target nucleic acid in a cell sample, the method comprising:

a) contacting a surface comprising an anion exchange moiety with a sample under conditions suitable to induce binding between the cell and the surface;

b) separating the surface containing the bound cells from the remaining sample to collect the cells;

c) releasing the nucleic acid from the cell;

d) forming a hybrid between the target nucleic acid and the probe specific for the target nucleic acid; and

e) detecting the presence or absence of the hybrid.

2. The method of claim 1, wherein the surface comprising the anion exchange moiety is not separated prior to step d).

3. The method of claim 1 or 2, wherein the surface comprising anion exchange moieties has at least 2, at least 3, at least 4, at least 5, at least 6, or all of the following characteristics:

i. the anion exchange moiety comprises an amine group;

the surface comprises polyethyleneimine as the anion exchange moiety;

the anion exchange moiety is resistant to degradation under the conditions used in step d);

the surface is provided by a particle;

v. the surface is provided by magnetic particles;

said surface is provided by particles having an average size of 5 μm or less, 3 μm or less, 2 μm or less and 1.5 μm or less; and/or

The surface is provided by magnetic particles comprising carboxyl groups at the surface of the particles, wherein at least a portion of the carboxyl groups are functionalized with polyethyleneimine to provide an anion exchange moiety.

4. Method according to one or more of claims 1 to 3, characterized in that in the cell sample the cells are contained in a liquid medium, preferably a liquid-based cytology medium.

5. The method according to claim 3 or 4, wherein the surface comprising the anion exchange moiety is provided by magnetic particles, wherein after contacting the magnetic particles with the sample, the concentration of the magnetic particles in the resulting mixture is selected from the group consisting of: 50-2000. mu.g/ml, 75-1750. mu.g/ml, 100-1500. mu.g/ml, 125-1250. mu.g/ml and 150-1100. mu.g/ml.

6. The method according to one or more of claims 1 to 5, wherein in step a) cell binding occurs at a pH value selected from the pH range of 3 to 8.5, 3.5 to 8.0, 3.5 to 7.75, 3.5 to 7.5, 3.5 to 7.25 or 3.75 to 7.

7. The method according to one or more of claims 1 to 6, wherein in step c) the collected anion exchange surface bound cells are contacted with a liquid composition that promotes the release of nucleic acids from the cells, wherein, optionally, in step c) a heating step is performed to promote the release and/or denaturation of nucleic acids.

8. The method of claim 7, wherein the liquid composition has one or more, preferably at least two, at least three and more preferably all of the following characteristics i to v:

i. it comprises a chaotropic agent;

it has an alkaline pH;

it has a pH selected from: pH12 or higher, pH12.5 or higher, pH 13 or higher, or pH 13.25 or higher;

it comprises one or more additives, preferably

aa) a chelating agent;

bb) a buffer; and/or

cc) preservative

v. the liquid composition is obtained by mixing two or more compositions, wherein one of the compositions comprises a chaotropic agent and one of the compositions is an alkaline solution comprising an alkaline agent.

9. The method according to one or more of claims 1 to 8, wherein the anion exchange surface is provided by magnetic particles comprising polyethyleneimine as anion exchange moiety, wherein the magnetic particles are not removed between steps c) and d).

10. The method according to one or more of claims 1 to 9, wherein a hybrid capture assay is performed, wherein steps d) and e) comprise the following steps:

step d)

-contacting the sample containing the released and denatured nucleic acids with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single-stranded target nucleic acid molecules to form double-stranded nucleic acid hybrids, wherein RNA/DNA hybrids are preferably formed;

-capturing double-stranded nucleic acid hybrids using a binding agent that binds to the double-stranded nucleic acid hybrids;

-optionally separating the double-stranded nucleic acid hybrid from unbound nucleic acids;

step e)

-detecting the presence or absence of a double-stranded nucleic acid hybrid, thereby indicating the presence or absence of the target nucleic acid.

11. The method according to claim 10, wherein the surface is provided by magnetic particles, wherein the magnetic particles are present during production and capture of the hybridosomes and are not removed in step d) by means of a magnet, but prior to performing detection step e), when separating the remaining sample and/or performing one or more washing steps.

12. Method according to one or more of claims 1-11, characterized in that the method comprises the following steps d) and e)

Step d)

-contacting the sample containing the released and denatured nucleic acids and magnetic particles for binding to cells with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single stranded target nucleic acid molecules to form double stranded nucleic acid hybrids;

-capturing the double stranded nucleic acid hybrid;

-separating the double stranded nucleic acid hybrids from unbound nucleic acids, thereby also removing at least a part of the magnetic particles;

step e)

-detecting the presence or absence of a double-stranded nucleic acid hybrid.

13. Method according to one or more of claims 1-12, characterized in that the method comprises the following steps d) and e)

Step d):

-contacting the sample containing the released and denatured nucleic acids and magnetic particles for binding to cells with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single stranded target nucleic acid molecules to form double stranded nucleic acid hybrids;

-capturing the double-stranded nucleic acid hybrid with a first binding agent that binds to the double-stranded nucleic acid hybrid, thereby forming a double-stranded nucleic acid hybrid/first binding agent complex;

-separating the double stranded nucleic acid hybrid/first binding agent complex from unbound nucleic acids, thereby also removing at least a portion of said magnetic particles;

-binding the complex to a further binding agent labelled with a detectable label to form a double stranded nucleic acid hybrid/first binding agent/labelled binding agent complex;

-washing the double stranded nucleic acid hybrid/first binding agent/labelled binding agent complex, wherein said washing removes remaining magnetic particles, if still present;

step e)

-detecting the presence or absence of the label of the other binding agent, thereby indicating the presence or absence of the target nucleic acid.

14. The method according to one or more of claims 1-13, characterized in that it comprises the steps of:

a) contacting a surface comprising an anion exchange moiety with a cell sample under conditions suitable to induce binding between the cells and said surface, wherein cell binding occurs at a pH at which the anion exchange groups of said anion exchange moiety are positively charged, preferably at a pH selected from the following pH ranges: 3-8.5, 3.5-8, 3.75-7.75, 4-7.5, 4.25-7.25 or 4.5-7;

b) separating the cell-bound surface from the remaining sample to collect cells;

c) releasing nucleic acids from the cells and denaturing the released nucleic acids;

d) generating a hybrid between a target nucleic acid and a probe specific for the target nucleic acid, wherein step d) comprises:

-contacting the sample containing released and denatured nucleic acids with one or more target nucleic acid specific probes, preferably forming RNA/DNA hybrids, under conditions that allow hybridization of the probes to single-stranded target nucleic acid molecules to form double-stranded nucleic acid hybrids;

-capturing the double-stranded nucleic acid hybrid using a binding agent that binds to the double-stranded nucleic acid hybrid;

-optionally separating the captured double stranded nucleic acid hybrids from unbound nucleic acids;

-optionally washing the captured double stranded nucleic acid hybrids;

e) detecting the presence or absence of the double-stranded nucleic acid hybrid, thereby indicating the presence or absence of the target nucleic acid.

15. The method according to one or more of claims 1-14, in particular claim 3, comprising the steps of:

a) contacting a surface comprising an anion exchange moiety with a cell sample under conditions suitable to induce binding between cells and the surface, wherein the anion exchange moiety comprises at least one primary amine, at least one secondary amine, and/or at least one tertiary amine group, wherein cell binding occurs at a pH value selected from the following pH ranges: 3.5-8, 3.75-7.75, 4-7.5, 4.25-7.25, or 4.5-7, wherein the amino groups of the anion exchange moiety are positively charged at the pH, wherein the binding conditions are not adjusted;

b) separating the cell-bound surface from the remaining sample to collect cells;

c) contacting the collected anion exchange surface-bound cells with a liquid composition that promotes the release of nucleic acids from the cells, wherein the liquid composition has one or more, preferably at least two, at least three, more preferably all of the following characteristics i to v:

i. it comprises a chaotropic agent;

it has an alkaline pH;

it has a pH selected from: pH12 or higher, pH12.5 or higher, pH 13 or higher, or pH 13.25 or higher;

it comprises one or more additives, preferably

aa) a chelating agent;

bb) a buffer; and/or

cc) preservative

And/or

v. the liquid composition is obtained by mixing two or more compositions, wherein one of the compositions comprises a chaotropic agent, one of the compositions is an alkaline solution comprising an alkaline agent (preferably NaOH or KOH), preferably in a concentration of 1.0N to 2.0N;

and releasing the nucleic acid from the cell and denaturing the released nucleic acid, wherein the heating step is preferably performed to facilitate release and/or denaturation of the nucleic acid;

d) generating a hybrid between the target nucleic acid and a probe specific for the target nucleic acid, wherein step d) comprises:

-contacting the sample containing released and denatured nucleic acids with one or more target nucleic acid specific probes, preferably forming RNA/DNA hybrids, under conditions that allow hybridization of the probes to single-stranded target nucleic acid molecules to form double-stranded nucleic acid hybrids;

-capturing the double-stranded nucleic acid hybrid using a binding agent that binds to the double-stranded nucleic acid hybrid;

-optionally separating the captured double stranded nucleic acid hybrids from unbound nucleic acids;

-optionally washing the captured double stranded nucleic acid hybrids;

e) detecting the presence or absence of a double-stranded nucleic acid hybrid, thereby indicating the presence or absence of the target nucleic acid.

16. The method according to one or more of claims 1-14, in particular according to claim 3 and/or claim 9, comprising the steps of:

a) contacting a surface comprising an anion exchange moiety with a cell sample under conditions suitable to induce binding between the cells and said surface, wherein said anion exchange surface is provided by magnetic particles comprising an anion exchange moiety, wherein cell binding occurs at a pH value selected from the group consisting of: 3.5-8, 3.75-7.75, 4-7.5, 4.25-7.25 or 4.5-7, wherein the anion exchange groups of the anion exchange moiety are positively charged at said pH, wherein preferably no adjustment of the binding conditions is made;

b) separating the magnetic particles with the cells bound thereto from the remaining sample to collect the cells;

c) contacting the collected magnetic particle-bound cells with a liquid composition that promotes the release of nucleic acids from the cells, wherein the liquid composition has one or more, preferably at least two, at least three, more preferably all of the following characteristics i to v:

i. it comprises a chaotropic agent;

it has an alkaline pH;

it has a pH selected from: pH12 or higher, pH12.5 or higher, pH 13 or higher, or pH 13.25 or higher;

it comprises one or more additives, preferably

aa) a chelating agent;

bb) a buffer; and/or

cc) preservative

And/or

v. the liquid composition is obtained by mixing two or more compositions, wherein one of the compositions comprises a chaotropic agent, one of the compositions is an alkaline solution comprising an alkaline agent (preferably NaOH or KOH), preferably at a concentration of 1.0N to 2.0N;

and releasing the nucleic acid from the cell and denaturing the released nucleic acid, wherein the heating step is preferably performed to facilitate release and/or denaturation of the nucleic acid;

d) generating a hybrid between the target nucleic acid and a probe specific for the target nucleic acid, wherein the magnetic particles are not magnetically separated prior to step d), wherein step d) comprises:

-contacting the sample containing the released and denatured nucleic acids and magnetic particles for binding to cells with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single stranded target nucleic acid molecules to form double stranded nucleic acid hybrids;

-capturing the double-stranded nucleic acid hybrid with a first binding agent that binds to the double-stranded nucleic acid hybrid, thereby forming a double-stranded nucleic acid hybrid/first binding agent complex;

-separating the double stranded nucleic acid hybrid/first binding agent complex from unbound nucleic acids, thereby also removing at least a portion of the magnetic particles;

-binding the complex to another binding agent labelled with a detectable label to form a double stranded nucleic acid hybrid/first binding agent/labelled binding agent complex;

-washing the double stranded nucleic acid hybrid/first binding agent/labelled binding agent complex, wherein said washing removes remaining magnetic particles, if still present;

e) detecting the presence or absence of a double-stranded nucleic acid hybrid, thereby indicating the presence or absence of the target nucleic acid.

17. The method according to one or more of claims 1 to 16, in particular claims 14 to 16, wherein the surface comprising anion-exchange moieties is provided by magnetic particles comprising polyethyleneimine as anion-exchange moiety, wherein, after contacting the magnetic particles with the cell sample in step a), the magnetic particles are contained in the resulting mixture in a concentration preferably of: 50-2000. mu.g/ml, 75-1750. mu.g/ml, 100-1500. mu.g/ml, 125-1250. mu.g/ml and 150-1100. mu.g/ml.

18. The method of claim 17, wherein in step c) the collected magnetic particle-bound cells are contacted with a volume of the liquid composition selected from the group consisting of: 50 μ l to 200 μ l, 60 μ l to 175 μ l, 70 μ l to 150 μ l, 80 μ l to 125 μ l and 85 μ l to 100 μ l, wherein the liquid composition comprises a chaotropic agent having a pH selected from the group consisting of: pH12 or higher, pH12.5 or higher, pH 13 or higher, or pH 13.25 or higher.

19. The method according to one or more of claims 1 to 18, having one or more, preferably at least two, more preferably at least three of the following features i to ix:

i. the method is an automated method for analyzing a clinical sample for a disease state and/or for determining the presence or absence of a pathogen in a clinical sample;

the target nucleic acid to be detected is a pathogen nucleic acid;

the target nucleic acid to be detected is a viral nucleic acid;

the target nucleic acid to be detected is an HPV nucleic acid;

v. the method is for HPV diagnosis;

the cells contained in the cell sample are epithelial cells;

the cells contained in the sample are cervical cells;

said cell sample is collected from a group consisting ofAnd

The method is an automated method for determining the presence or absence of HPV nucleic acids, preferably high-risk HPV nucleic acids, in a cervical sample collected in a liquid-based cytology medium.

20. A kit for use in the method of one or more of claims 1-19, comprising:

a) magnetic particles, wherein the surface of the magnetic particles comprises an anion exchange moiety;

b) a denaturant which is an alkaline solution containing an alkali (preferably NaOH or KOH), preferably in a concentration range of 1.0N to 2.0N; and

c) a composition comprising a chaotropic agent and optionally one or more additives selected from the group consisting of chelating agents, buffers and preservatives.

21. The kit of claim 20, comprising a kit comprising a plurality of wells, wherein

a) The first tank of the kit contains magnetic particles, wherein the surfaces of the magnetic particles comprise an anion exchange moiety;

b) the second tank of the kit contains a denaturant, which is an alkaline solution containing a base (preferably NaOH or KOH), preferably at a concentration of 1.0N-2.0N; and

c) the third tank of the kit comprises a composition comprising a chaotropic agent and optionally one or more additives selected from the group consisting of chelating agents, buffers and preservatives,

wherein optionally, the kit is sealed.

22. The kit of claim 20 or 21, wherein the magnetic particles have one or more of the following characteristics:

i) the magnetic particles are functionalized with polyethyleneimine as the anion exchange moiety;

ii) the magnetic particles are contained in a particle suspension having a pH selected from the group consisting of: 7.5 or less, 7 or less, and 6.5 or less; and/or

iii) the magnetic particles are contained in a particle suspension, wherein the particles are contained in the suspension at a concentration selected from the group consisting of: 5mg/ml to 50mg/ml, 10mg/ml to 20mg/ml and 12.5mg/ml to 17.5 mg/ml.

23. The kit according to one or more of claims 20 to 22, characterized in that it has one or more of the following characteristics:

a) the kit comprises an elution plate comprising a plurality of wells;

b) the kit comprises at least one probe suitable for hybridization to a target nucleic acid, wherein said probe is preferably an RNA probe;

c) the kit comprises at least one binding agent capable of binding double-stranded nucleic acid hybrids, wherein the binding agent is preferably attached to a solid support;

d) the kit comprises one or more wash buffers;

e) the kit comprises at least one further binding agent comprising a detectable label, preferably alkaline phosphatase;

f) the kit comprises one or more detection reagents;

and/or

g) The kit comprises at least one probe suitable for hybridization to a HPV target nucleic acid.

Technical Field

The present invention relates to methods for detecting the presence or absence of a target nucleic acid in a liquid sample containing cells.

Background

To detect the presence or absence of a target nucleic acid, several methods are known in the art based on capturing a hybrid comprising the target nucleic acid to be detected, herein referred to as hybrid capture assay. The basis of each technique is described, for example, in WO 93/10263, and further developments are described in WO 2010/127223. Techniques are used to detect and characterize specific nucleic acid sequences and sequence changes, such as detecting the presence or absence of viral or bacterial nucleic acid sequences indicative of infection, the presence of variants of alleles of disease and cancer-associated mammalian genes, and the identification of the source of nucleic acids found in forensic samples, as well as fetal diagnostics, such as paternity testing. Said techniques based on hybrid capture are widely used for the detection of DNA or RNA (reverse hybrid capture), in particular in the field of clinical diagnostics. The FDA approved test is the digene HC2HPV DNA assay, which uses a manual conversion procedure to process both types

AndLBC medium for subsequent testing by gene HC2 High-Risk HPV DNA assay. The corresponding manual solution requires a time-consuming, manual switching method involving many repetitive actions. To collect the cells in a clinical sample, they must be centrifuged, the supernatant must be removed, and the cells prepared for subsequent assays. High volume laboratories that process 500 to 2500 samples per day are subject to a great deal of ergonomically relevant damage, such as carpal tunnel syndrome, due to repeated manual steps, which is also present to a lesser extent in lower volume laboratories. Therefore, there is a great need in the art to avoid manual steps and automation of sample preparation.

An automated method for preparing samples for each hybrid capture assay was performed by QIAGEN IncThe AXpH DNA program was developed by the name. This is a DNA extraction protocol based on anion exchange chromatography, and up to 96 samples can be prepared automatically in 4.5 to 6.5 hours, depending on the cytological medium used. Due to the fixation of formaldehyde, is collected inSamples in media requiring improved protocols for extended cell lysis time and addition of proteinase K to fix from formaldehydeThe sample is purified of DNA. This extended run time made it impossible for customers to process 88 samples of full disks in one shift (8 hours) along with calibrators and controls, including hc test. Thus, the need for customers to achieve faster turnaround times with high throughput HPV testing and to reduce the number of manual interventions remains unresolved.

It is an object of the present invention to provide a method for rapidly and suitably automatically detecting the presence or absence of a target nucleic acid in a cell sample.

Summary of The Invention

The present invention provides a rapid and automatable method wherein cells, such as epithelial cells derived from a cervical swab sample, are bound to an anion exchange surface and thereby collected from the surrounding liquid medium. The invention is particularly suited to the collection of cells from liquid-based cytology media. The cells bind directly with high affinity and fast kinetics to the anion exchange surface, which is preferably provided by magnetic particles carrying anion exchange moieties. Cells bound to the anion exchange surface are easily separated from the surrounding medium and can be directly resuspended in a composition suitable for a subsequent hybridization capture assay, which is performed to detect nucleic acids, such as pathogen nucleic acids, in particular viral nucleic acids or cellular nucleic acids. Furthermore, it was surprisingly found that it is not necessary to actively remove, respectively separate, the anion exchange surface prior to performing the hybrid capture assay. This significantly reduces the necessary preparation steps. Thus, the method of the present invention provides a considerable improvement over existing manual or automated sample preparation methods, as it is fast, automated, and requires only a small number of preparatory steps. In contrast to the prior art methods, no time-consuming manual cell preparation steps are required and, furthermore, no special pre-treatments, such as adjustment of the binding conditions, are required. This saves chemistry (reagents) and also has the advantage that the overall operating capacity of the robotic system can be used for the sample volume. As shown in the examples, this method provides reliable results and is not prone to errors, which is an important feature in the field of diagnostics. The present invention thus provides a solution to the above customer needs.

According to a first aspect, there is provided a method of determining the presence or absence of a target nucleic acid in a cell sample, the method comprising:

a) contacting a surface comprising an anion exchange moiety with a cell sample under conditions suitable to induce binding between said cell and said surface;

b) separating the surface containing the bound cells from the remaining sample to collect the cells;

c) releasing the nucleic acid from the cell;

d) forming a hybrid between the target nucleic acid and the probe specific for the target nucleic acid;

e) detecting the presence or absence of the hybrid.

As shown in the examples, this method enables rapid preparation of cell samples for use in hybrid capture assays and thus rapid performance of hybrid capture assays. The method is reliable, rapid and suitable for automation. It is therefore particularly suitable for use in the diagnostic field. Furthermore, the method is particularly useful for high throughput applications.

Also provided is a kit for use in the method of the invention, comprising:

a) magnetic particles, wherein the surface of the magnetic particles comprises an anion exchange moiety;

b) a denaturant which is an alkaline solution containing an alkali, preferably NaOH or KOH; and

c) a composition comprising a chaotropic agent and optionally one or more additives selected from the group consisting of chelating agents, buffers and preservatives.

The corresponding kit is used for the rapid preparation of cell samples for hybrid capture assays. Preferably, the kit is provided in the form of a kit, wherein the kit components a) to c) are comprised in separate tanks of the kit. The corresponding cartridge is suitable for a robotic system capable of handling magnetic particles.

Also provided is a kit for performing a hybrid capture assay, comprising:

a) magnetic particles, wherein the surface of the magnetic particles comprises an anion exchange moiety;

b) at least one probe suitable for hybridization to a target nucleic acid; and

c) at least one binder capable of binding double stranded nucleic acid hybrids.

Other objects, features, advantages and aspects of the present application will become apparent to those skilled in the art from the following description and the appended claims. It should be understood, however, that the following description, appended claims, and specific examples, while indicating preferred embodiments of the application, are given by way of illustration only. Various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from reading the following disclosure.

Brief Description of Drawings

FIG. 1: comparison of manual AXpH-direct and manual switch I. The HPV assay results (RLU/CO [ MW ]) shown are the results of HPV negative clinical samples using different bead suspensions I-VII. Manual Conversion (MC) was used as reference.

FIG. 2: comparison of manual AXpH-direct and manual switch II. The HPV assay results (RLU/CO [ MW ]) shown are the results of HPV positive clinical samples using different bead suspensions I-VII. Manual Conversion (MC) was used as reference.

FIG. 3: adaptation of AXpH-direct to Automation I. The HPV assay results (RLU/CO [ MW ]) shown are the results of HPV negative clinical specimens using Manual Conversion (MC) as reference, manual AXpH-direct protocol and automated AXpH-direct protocol.

FIG. 4: suitability of AXpH-direct for automation II. The HPV assay results (RLU/CO [ MW ]) shown are the results of HPV positive SiHa cell cultures using manual switching (MC) as reference, manual AXpH-direct protocol and automated AXpH-direct protocol.

FIG. 5: suitability of AXpH-direct for automation III. The HPV assay results (RLU/CO [ MW ]) shown are the results of HPV positive samples from clinical bank (Bank 1) using Manual Conversion (MC) as reference, manual AXpH-direct protocol and automated AXpH-direct protocol.

FIG. 6: suitability of AXpH-direct for automated IV. The HPV assay results (RLU/CO [ MW ]) shown are the results of HPV positive samples from another clinical bank (Bank 2) using Manual Conversion (MC) as reference, manual AXpH-direct protocol and automated AXpH-direct protocol.

FIG. 7: AXpH-direct to

And

sample suitability. Display deviceThe indicated HPV assay results (RLU/CO) are the results of different HPV positive (clinical pool) and negative clinical samples (negative pool) and HPV positive cell cultures (cells) using manual switching (MC) as reference, manual AXpH-direct protocol or automated AXpH-direct protocol. The sample contains

(PC) or(SP) Medium.

FIG. 8: parameters responsible for cell binding to bead I. The HPV assay results (RLU/CO) shown are the results of using bead fractions and supernatant fractions (SN) under different cell-to-bead binding conditions ( pH 5, 7 or 9, iPrOH ═ isopropanol). Beads or silica beads (MAS G) were modified with PEI.

FIG. 9: parameters responsible for cell binding to bead II. The HPV assay results (RLU/CO) shown are the results of the bead fraction and supernatant fraction using different cell-to-bead binding conditions ( pH 5, 7 or 9, iPrOH ═ isopropanol). DEAPS modified beads or silica beads (MASG) were used.

FIG. 10: parameters responsible for cell binding to bead III. The HPV assay results (RLU/CO) shown are the results of using bead fractions under different cell-to-bead binding conditions ( pH 5, 7 or 9, iPrOH ═ isopropanol). PEI modified beads and DEAPS modified beads were compared.

FIG. 11: HPV identity determination result I. The results of the HPV assay (RLU/CO ═ 0,1-10,000) shown are replicates of 72 individual samples. For comparison between the manual switch (MC) and manual AXpH-direct protocols, each RLU/CO value was plotted as an x-y plot. r is²Is the correlation coefficient.

FIG. 12: influence of elution buffer. The resulting HPV assay results (RLU/CO [ MW ]) shown are the results of applying 2000. mu.l or 700. mu.l samples to an automated AXpH-direct protocol (QS-SP-2000. mu.l protocol or 700. mu.l protocol, respectively) and applying STM/DNR or NaOH as elution buffer. Manual Conversion (MC) was used as reference.

FIG. 13: parameters responsible for cell binding to bead IV. The HPV assay results (RLU/CO) shown are the results of using bead fractions under different cell-to-bead binding conditions ( pH 5, 7 or 9, iPrOH ═ isopropanol). PEI modified beads and DEAPS modified beads were compared. Manual Conversion (MC) was used as a reference with 700. mu.l of sample input.

FIG. 14: influence of conductivity during cell binding. The HPV assay results (RLU/CO) shown are the application of different concentrations of KH during the binding of cells to PEI modified beads₂PO₄(0-1000mM) eluent fraction and supernatant fraction. Manual Conversion (MC) was used as reference.

FIG. 15: effect of sample acidification and dilution. The HPV assay results (RLU/CO) shown are the results of the eluate fraction when undiluted, water or acetic acid diluted samples were subjected to the manual AXpH-direct protocol. Beads were modified with PEI. Manual Conversion (MC) was used as reference.

FIG. 16: the amount of beads I was optimized. The HPV assay results (RLU/CO) shown are the results of applying different volumes of the eluent portion of PEI modified bead suspensions. Manual switching (no beads) was used as reference.

FIG. 17: the amount of beads II was optimized. The HPV assay results (RLU/CO) shown are the results of applying different volumes of the eluent and supernatant fractions of PEI modified bead suspensions. Manual Conversion (MC) was used as reference.

FIG. 18: binding of cell culture controls. The HPV assay results (RLU/CO) shown are the results of the eluent and supernatant fractions when different volumes of PEI modified bead suspension were used. SiHa and HeLa cells were used as samples. Manual Conversion (MC) was used as reference.

Fig. 19a) and b): an interfering substance. The obtained HPV assay results (RLU/CO) are shown with various interferents (CJ ═ contraceptive jelly, LJ ═ lubricant jelly, AC ═ antifungal cream, CS ═ contraceptive spermicide, D ═ irrigant) added to the samples and the AXpH-direct method applied. The corresponding sample without interference was used as reference (w/o Inh).

FIG. 20: detection limit. The resulting HPV assay results (RLU/CO) shown are the results using different dilutions of samples from a clinical pool of HPV positive (pool, dilutions 1-5) and using manual switch (MC) or AXpH-direct method. For each dilution, positive clinical pool samples that tested positive can be seen from the table on the right. HPV negative clinical pool (negative pool) served as control.

FIG. 21: effect of cellular organization (cellularity) on cell binding. The resulting HPV assay results (RLU/CO) shown are the results of using different dilutions (8X-1/128X) of samples from HPV positive clinical pools and applying manual switching (MC) or automated AXpH-direct method. HPV negative clinical pool (negative pool) served as control.

FIG. 22: effect of elution volume. The resulting HPV assay results (RLU/CO) are shown when different volumes of STM/DNR are applied for elution. Manual Conversion (MC) was used as reference.

FIG. 23: influence of sample input volume. The resulting HPV assay results (RLU/CO) are shown as the results when different volumes of sample input were used. Samples from two different clinical pools (pool 1 and pool 2) were used. AXpH beads were used, hand-switched (MC) as reference.

FIG. 24: modification of beads with PEI to prepareAnd (3) sampling. The resulting HPV HC assay results (RLU/CO) shown are the results of two different HPV positive clinical pools (pool 1 and pool 2). Manual Conversion (MC) with 2.0ml sample input was used as a reference.

FIG. 25: PEI modified beads (Sample) was analyzed for binding efficiency. The resulting HPV HC assay results (RLU/CO) shown are the results of the supernatant and eluate fractions of clinical library samples using different volumes of bead suspension (bead volumes). Manual Conversion (MC) with 2.0ml sample input was used as a reference.

FIG. 26: automatic sample preparation I: (Sample) bead volume fine tuning. The resulting HPV HC assay results (RLU/CO) are shown for HPV low positive SiHa cells (top) and HeLa cell cultures (bottom) using different volumes of PEI modified bead suspension (bead volumes)Results for the sample of (1). Manual Conversion (MC) with 2.0ml of sample input was used as a reference.

FIG. 27 is a schematic view showing: automatic sample preparation II (Sample) bead volume fine tuning. The resulting HPV HC assay results (RLU/CO) shown are for samples of HPV medium/high positive SiHa cells (top) and HeLa cell cultures (bottom) using different volumes of PEI modified bead suspension (bead volumes). Manual Conversion (MC) with 2.0ml of sample input was used as a reference.

FIG. 28: automatic sample preparation III: (

Sample) bead volume fine tuning. The resulting HPVHC assay results (RLU/CO) shown are the results for samples of HPV high (top), medium (middle) and low (bottom) positive clinical pools using different volumes of PEI modified bead suspension (bead volumes). Manual Conversion (MC) with 2.0ml of sample input was used as a reference.

FIG. 29: automatic AXpH-direct method (AXpH) and RCS (Rapid Capture System) (AXpH-Rapid Capture)

Samples) are determined. The resulting HPV HC assay results (RLU/CO) shown are for samples of negative and positive clinical banks as well as SiHa cell culture samples. The HC2.0 measurement was performed differently. Manual Conversion (MC) with 2.0ml of sample input was used as a reference.

FIG. 30: reference HPV HC assay results (Samples), consistent with Manual Conversion (MC). The HPV assay results shown are duplicates of 394 independent items. For comparison between the Manual Conversion (MC) and the automated AXpH-direct protocol, each RLU/CO value was plotted as an x-y plot. r is²Is the correlation coefficient.

FIG. 31: by increasing the sample input amount (

Samples) to enhance HPV HC assay sensitivity. The resulting HPV assay results (RLU/CO) shown are for samples of Caski cell cultures and samples of low positive clinical pools using different volumes of sample input. Manual Conversion (MC) was used as reference.

Fig. 32a and b: manual conversion with AXpH-direct method 2X2 and Scatter plot analysis (Scatter plotsanalysis). Analyze PrequotAnd (3) sampling.

Fig. 33a and b: manual conversion with 2X2 and scatter plot analysis of AXpH-direct method. Analysis of residual PrequotAnd (3) sampling.

Detailed Description

The present invention provides a method that enables the collection of cells using an anion exchange surface to prepare the cells for subsequent target nucleic acid detection. The method can be used, for example, for laboratory research and clinical diagnostic purposes, including but not limited to, detection and identification of pathogenic organisms or viruses, detection of genetic susceptibility to particular diseases, and in the diagnostic field of tumors or other diseases. In particular, it can be used in the field of viral detection, in particular the detection of HPV.

According to a first aspect, the present invention provides a method of determining the presence or absence of a target nucleic acid in a cell sample, the method comprising:

a) contacting the surface comprising the anion exchange moiety with a liquid cell sample under conditions suitable to induce binding of the cells to the surface;

b) separating the surface containing the bound cells from the remaining sample to collect the cells;

c) releasing nucleic acid from the cell;

d) generating a hybrid between a target nucleic acid and a probe specific to the target nucleic acid;

e) detecting the presence or absence of the hybrid.

Each individual step, materials used, and suitable and preferred embodiments are described in detail below.

Step A)

In step a), a cell sample is contacted with a surface comprising an anion exchange moiety under conditions suitable to induce binding of cells to said surface.

Surface of

The surface used in step a) is solid or semi-solid and comprises an anion exchange moiety. The term "surface" as used herein refers in particular to the part of a solid phase that is in contact with a liquid when the solid phase is in contact with a liquid. The surface provided by the solid phase provides (e.g. carries) an anion exchange moiety. The anion exchange portion will be described in detail below. Suitable solid phases may be made of or in particular may comprise on their surface a material selected from the group consisting of:

materials comprising or consisting of silicon, such as silica and polysilicic materials, quartz, borosilicate, silicate, diatomaceous earth or glass,

materials comprising or consisting of polymers such as poly (meth) acrylates, polyurethanes, polystyrenes (polystyrenes), polystyrenes (polystyrols), polyacrylamides, divinylbenzene polymers, styrene divinylbenzene polymers, polyethylenes, polypropylenes, polyvinylidene fluorides, polyacrylonitriles, polyvinyl chlorides, polyacrylates, polyacrylamides, polymethacrylates or methyl methacrylate polymers;

materials comprising or consisting of polysaccharides, such as agarose (agarose), cellulose, dextran or agarose (sepharose);

-a material comprising or consisting of minerals;

-materials comprising or consisting of metal oxides, such as alumina, magnesia, titania or zirconia;

-materials comprising or consisting of metals, such as gold or platinum; and

-materials comprising or consisting of derivatives of the above substances.

Furthermore, the solid phase may also comprise more than one of the above-mentioned materials. Preferably, the surface containing the anion exchange moieties is comprised of at least one of the above materials or a mixture thereof. Any solid phase suitable for anion exchange chromatography may also be used as a solid phase to provide a surface comprising anion exchange moieties, e.g., functionalized with anion exchange moieties.

Preferred forms of solid phases include, but are not limited to, particles such as beads, membranes, filters, plates, columns, containers, and dipsticks. According to one embodiment, the surface comprising the anion exchange moiety is provided by a container, e.g. the inner surface of the container is intended to receive a cell sample. The inner surface of the surface or portions thereof may be functionalized, e.g., coated, with anion exchange moieties. Examples of containers that can be functionalized with anion exchange moieties include, but are not limited to: microtubes and microplate wells. In this embodiment, the cells are bound to the inner surface of the container (e.g., well) by the anion exchange moiety provided, thereby facilitating collection of the cells from the sample.

According to a preferred embodiment, the surface may be provided by a solid phase, which may be provided as a suspension and may be separated from a liquid phase. When contacted with a liquid phase (e.g., a cytological medium based on a cell-containing liquid, which is an example of a cell sample), the surface containing the anion exchange moiety is contacted with the liquid phase for cell binding. The surface comprising the anion exchange moiety is preferably provided by particles comprising the anion exchange moiety at their surface. The average size of the particles may be selected from the following ranges: 100nm-50 μm, 200nm-40 μm, 300nm-35 μm, 400nm-30 μm, 450nm-25 μm, 500nm-20 μm, 550nm-15 μm, 600nm-12.5 μm, 650nm-10 μm, 700nm-7.5 μm, 750nm-5 μm, 800nm-3.5 μm, 800nm-3 μm, 800-2,5 μm, 800nm-2 μm and 800nm-1.5 μm. Particles of a corresponding size, in particular of a smaller size, are easy to handle and can be resuspended well in a cell sample, for example 10 μm or less, 7.5 μm or less, preferably 5 μm or less, 2.5 μm or less, or 1.5 μm or less. In addition, the corresponding small particles provide a large surface area that can bind and thus efficiently collect cells from the remaining sample (e.g., a liquid-based cytology collection medium). Furthermore, smaller particles are easily removed in step d) without the need for a magnetic separation step. Suitable materials for providing or preparing the particles are described above. The particles may also comprise more than one of the above materials, for example comprising two or more layers comprising or made of different materials, to provide a particle body. Suitable embodiments are also described below.

Preferably, magnetic particles are used to provide an anion exchange surface to which cells are bound. The use of magnetic particles has the advantage that they can be treated and moved by means of a magnetic field. The magnetic particles may have e.g. superparamagnetic, paramagnetic, ferrimagnetic or ferromagnetic properties. Preferably, superparamagnetic particles are used. The magnetic particles may comprise a magnetic material incorporated into and/or bound to the particles. To avoid leaching of the magnetic material, the magnetic material is preferably completely encapsulated, for example by a surface-providing material such as silica, polysilicic acid, glass or a polymeric material such as polyacrylate. The magnetic material may provide one or more cores of the particles, may be contained in the core and/or may be coated on the core of the particles.

According to one embodiment, the particles comprise a polymer core, such as a core made of polystyrene, surrounded by at least one polymer layer, preferably at least two polymer layers, preferably a polyethylene layer and/or a polyacrylate layer. Preferably the particle surface consists of or comprises polyacrylate. The particle surface is then functionalized with an anion exchange moiety, preferably polyethyleneimine. If magnetic particles are utilized, a magnetic material, such as iron oxide, may be deposited on the polystyrene core. Followed by the application of at least one, preferably at least two polymer layers as described above, and then surface functionalization of the resulting magnetic particles with an anion exchange moiety, preferably polyethyleneimine, to provide the final magnetic particles with an anion exchange surface.

Anion exchange moieties

In the present invention, the surface used to bind cells from a cell sample and thereby collect the cells comprises an anion exchange moiety. The anion exchange portion includes one or more groups capable of anion exchange, such as amine groups. The anion exchange moiety is capable of binding anions under suitable conditions, particularly at a suitable pH. However, they need not be associated with anions.

According to one embodiment, the anion exchange moiety is provided by a surface material of the solid phase. This embodiment is suitable if the material from which the surface is made contains anion exchange groups that are accessible to the cells when the surface is in contact with a liquid. The anion exchange moiety may also form part of a compound or composition that is bound to the surface of the solid phase. The surface is preferably functionalized with one or more anion exchange moieties comprising one or more anion exchange groups. The term "portion" does not include any limitation on size. If the moiety comprises more than one anion exchange group, the same or different anion exchange groups may be present in the same moiety. Examples of suitable anion exchange moieties include, but are not limited to, monoamines, diamines, polyamines, and nitrogen-containing aromatic or aliphatic heterocyclic groups as well as cyclic, aromatic, and heterocyclic amines. Preferably, the anion exchange moiety comprises at least one primary, secondary and/or tertiary amino group. In a preferred embodiment, the anion exchange moiety comprises or consists of a primary, secondary or tertiary amine represented by the formula:

R₃N、R₂NH、RNH₂and/or X- (CH)₂)_n-Y

In the formula

X is R₂N, RNH or NH₂，

Y is R₂N, RNH or NH₂，

R is, independently of one another, a linear, branched or cyclic alkyl, alkenyl, alkynyl or aryl substituent which may comprise one or more heteroatoms, preferably selected from O, N, S or P, and

n is an integer from 0 to 20, preferably from 0 to 18.

Thus, the anion exchange moiety comprises an anion exchange group and optionally may have a plurality of anion exchange groups which may be the same or different from each other. The anion exchange groups are preferably chemical groups which are neutral or uncharged at high pH values and which are protonated at low pH values and thus have a positive charge. The positively charged pH of the anion exchange group depends on its pKa. The pKa value of the anion exchange group may be in the range of about 7.5 to 14, 8 to about 14, preferably about 8.5 to about 13.5, 8.75 to 13, more preferably 9 to 12.5, 9.25 to 12, 9.5 to 11.5 or about 9.5 to about 11. A pKa value of at least 8, preferably at least 8.5, more preferably at least 9, most preferably at least 9.5 is advantageous because at low to moderate pH values the anion exchange moiety is positively ionized and thus positively charged. This ensures strong binding of cells over the wide pH range and thus pH values routinely provided by standard cell samples. Thus, in most cases, the binding conditions do not need to be specifically adjusted, since at least part of the anion exchange groups are positively charged at the pH value or pH environment provided by the cell sample, thereby allowing cell binding.

The anion exchange moiety is positively ionized at an appropriate pH to attract and bind negatively charged molecules, particularly cells contained in a cell sample. As shown in the examples, the anion exchange moiety is capable of binding cells, such as in particular cervical cells, with high efficiency. Preferably, the anion exchange surface used in the process of the present invention is resistant to degradation by lytic enzymes, proteases, chemicals and high temperatures of up to 85 ℃, preferably up to 90 ℃, more preferably up to 95 ℃. For example, PEI modified surfaces meet various requirements. The advantage of using correspondingly resistant anion exchange surfaces is that they do not degrade during step d), if the anion exchange surfaces are not removed before step d), separately from the remaining samples.

The amino group may bear alkyl, alkenyl, alkynyl and/or aromatic substituents, including cyclic substituents and substituents which, together with the nitrogen atom, form a heterocyclic or heteroaromatic ring. The substituent preferably contains 1 to 20 carbon atoms, more preferably 1 to 12, 1 to 8, 1 to 6, 1 to 5, 1 to 4, 1 to 3 or 1 or 2 carbon atoms. They may be straight-chain or branched and may include heteroatoms such as oxygen, nitrogen, sulfur, silicon and halogen (e.g. fluorine, chlorine, bromine) atoms, which may also be substituted. The substituents suitably comprise no more than 4, more preferably no more than 3, no more than 2 or no more than 1 heteroatoms.

In one embodiment, the anion exchange moiety carries 1 to 30, 1 to 25, 1 to 20, 1 to 15, 1 to 10, 2 to 8, or 2 to 6 amino groups.

Specific examples of anion exchange moieties include, but are not limited to: aminomethyl (AM), Aminoethyl (AE), aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, such as Diethylaminoethyl (DEAE), N-Diethylaminopropyltrimethoxysilane (DEAPS), ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, Trimethylamino (TMA), Triethylaminoethyl (TEAE), linear or branched Polyethyleneimine (PEI), carboxylated or hydroxyalkylated polyethyleneimine, polyetheramine (jeffamine), spermine, spermidine, 3- (propylamino) propylamine, Polyamidoamine (PAMAM) dendrimer, polyallylamine, polyvinylamine, N-morpholinoethyl, polylysine and tetraazacycloalkane. Preferred anion exchange moieties include dialkylamino groups, particularly diethylamino groups, or linear or branched Polyethyleneimine (PEI). Most preferably, the surface comprises moieties functionalized with polyethyleneimine to provide said anion exchange moieties, respectively. Linear Polyethylenimine (PEI) contains secondary amines, whereas branched PEI contains primary, secondary, and tertiary amine groups, in contrast. According to one embodiment, the anion exchange moiety is not a polypeptide or protein.

In one embodiment, the anion exchange moiety comprises an entity selected from the group consisting of: primary, secondary and tertiary monoamines and polyamines represented by the formula:

R₁R₂R₃N,

R₁R₂N(CH2)_nNR₃R₄,

R₁R₂N(CH2)_nNR₃(CH2)_mNR₄R₅,

R₁R₂N(CH2)_nNR₃(CH2)_mNR₄(CH2)_oNR₅R₆

R₁R₂N(CH2)_nNR₃(CH2)mNR₄(CH2)_oNR₅(CH2)_pNR₆R₇

R₁R₂N(CH2)_nNR₃(CH2)mNR₄(CH2)_oNR₅(CH2)_pNR₆(CH2)_qNR₇R₈

R₁R₂N(CH2)_nNR₃(CH2)_mNR₄(CH2)_oNR₅(CH2)_pNR₆(CH2)_qNR₇(CH2)_rNR₈R₉

R₁R₂N(CH2)_nNR₃(CH2)_mNR₄(CH2)_oNR₅(CH2)_pNR₆(CH2)_qNR₇(CH2)_rNR₈(CH2)_sNR₉R₁₀

in the formula

m, n, o, p, q, R and s independently of one another may be 2 to 8, R₁、R₂、R₃、R₄、R₅、R₆、R₇、R₈、R₉And R₁₀Which may be identical or different, are chosen from H, alkyl (branched or unbranched, saturated or unsaturated, preferably containing from 1 to 10C atoms) or aryl.

In one embodiment, the anion exchange moiety comprises N-propyl-1, 3-propanediamine or pentaethylenehexamine. In certain embodiments, the anion exchange moiety is selected from spermine or spermidine. As mentioned above, although it is preferred to functionalize the surface with polyethyleneimine, it is preferred that the particle surface, and more preferably the magnetic particle surface.

The surfaces of the present invention may comprise more than one type of anion exchange moiety, and may be functionalized with a variety of anion exchange moieties accordingly. Thus, two or more different anion exchange moieties may also be present on the surface. Thus, surfaces comprising a mixture of different anion exchange moieties are within the scope of the invention. However, it is also within the scope of the invention to use predominantly or exclusively one type of anion exchange moiety.

To functionalize the surface with the anion exchange moiety, several methods can be employed. The anion exchange moiety may be covalently or non-covalently bound directly to the surface by electrostatic means, and/or may form part of a polymer or other composition that forms a surface coating or is provided on the surface of the solid phase. The anion exchange moiety can also be precipitated on a solid phase. According to one embodiment, the anion exchange moiety is provided as a coating on the solid phase.

According to one embodiment, a covalent coupling strategy is employed. According to one embodiment, the solid phase comprises at its surface functional groups suitable for covalent attachment to anion exchange moieties. For example, the surface may comprise functional groups selected from the group consisting of: Si-O-Si, Si-OH, an alcohol, a diol or polyol, a carboxyl, an amine, a phosphate or a phosphonate. The anion exchange moiety may be attached to the solid phase, for example, by using an epoxide, a carboxyl group, particularly an activated carboxyl group, a silane, an anhydride, an acid chloride, a formyl group, a trifluoroethylsulfonyl (tresyl group), a pentafluorophenylsulfonyl chloride or a maleimide group. The functional group used for coupling the anion exchange moiety may be attached directly to the solid phase or via a (linear or branched) spacer group, e.g. a hydrocarbon, such as- (CH)₂) n-groups, carbohydrates, polyethylene glycol and polypropylene glycol are attached to a solid phase. Alternatively, it is also possible to provide the anion exchange moiety on the surface of the solid phase with a polymer consisting of monomers comprising anion exchange groups, such as amino functional groups. In certain embodiments, the solid phase material has a silicon-containing surface, such as a polysilicic acid surface, to which anion exchange moieties are coupled with silane groups. According to a preferred embodiment, the surface of the solid phase comprises carboxyl groups which can be used for covalent coupling of anion exchange moieties such as PEI. The corresponding carboxyl groups are preferably provided by a polyacrylate layer.

The anion exchange moiety may be attached to the surface of the solid phase via a linker group. The linking group is preferably a straight, branched or cyclic alkylene, alkenylene or alkynylene group, preferably containing 1 to 20 carbon atoms, more preferably 1 to 12, 1 to 8, 1 to 6, 1 to 5, 1 to 4, 1 to 3 or 1 or 2 carbon atoms. It may further comprise heteroatoms such as oxygen, nitrogen, sulphur, silicon and halogen (e.g. fluorine, chlorine, bromine) atoms, preferably not more than 4, more preferably not more than 3, not more than 2 or not more than 1 heteroatoms. In a preferred embodiment, the linking group is an alkylene (alkylene), in particular an alkylene (propylene) group.

According to one embodiment, to create an anion exchange surface, the surface is activated to facilitate or enable coupling of the anion exchange moieties. Chemical activation is preferably performed. Chemical activation includes, but is not limited to, the use of oxidizing agents. According to one embodiment, which is preferred if COOH groups are used for coupling, a carbodiimide, such as EDC (1-ethyl-3- (3-dimethylaminopropyl) carbodiimide), is used for activating the surface, in particular the surface with COOH groups. EDS is a carboxyl activating agent suitable for coupling amines to give amide bonds. However, EDC may also be used to activate the phosphate groups. EDC can be used in combination with N-hydroxysuccinimide (NHS), or sulfo-NHS, to improve coupling efficiency and/or to produce stable amine-reactive products.

Additional functionalization of surfaces

In certain embodiments, the surface comprises additional functional groups in addition to anion exchange groups. Non-limiting examples are described below. The functional groups may be provided by the surface material itself, for example acidic groups such as carboxyl groups (for example if the surface is made of polyacrylate), or each functional group may be provided by a ligand covalently or non-covalently attached to the surface. The functional groups can be applied to the surface as described herein for the anion exchange moieties.

According to one embodiment, the pKa value of the functional group is in the range of 0 to 7, preferably 1 to 5. Suitable examples include ion exchangers, in particular cation exchangers, preferably acidic groups, such as carboxyl groups. Other suitable groups include betaine, sulfonate, phosphonate, and phosphate groups. As described herein, the solid phase may comprise carboxyl groups to allow attachment to anion exchange moieties. When the anion exchange moiety is attached, the concentration of the anion exchange moiety can be selected such that at least a portion of the carboxyl groups are not bound to the anion exchange moiety, and thus, wherein the carboxyl groups are in contact at the surface.

According to one embodiment, the surface comprises inert ligands. In particular, the inert ligands are neutral or uncharged, preferably hydrophilic, at pH values in the range from 2 to 14, from 3 to 13, from 4 to 12. The inert ligands can be attached to the surface as described herein for the anion exchange moieties. Preferably, the inert ligand is an organic moiety, in particular an alkyl, alkenyl, alkynyl or aromatic moiety, which may be linear, branched or cyclic, and which preferably comprises at least one heteroatom, such as oxygen, nitrogen, sulphur, silicon and halogen (e.g. fluorine, chlorine, bromine) atoms. The inert ligand preferably comprises 1 to 20 carbon atoms, more preferably 1 to 12, 1 to 8, 1 to 6, 1 to 5, 1 to 4, 1 to 3 or 1 or 2 carbon atoms, and up to 4, more preferably up to 3, up to 2, or up to 1 heteroatom. Particularly preferred are inert ligands containing at least one hydroxyl group, especially at least 2 hydroxyl groups, such as ligands comprising a 2, 3-dihydroxypropyl group. A specific example of an inert ligand is (2, 3-dihydroxypropyl) oxypropyl. Inert ligands can be used to reduce the amount of anion exchange moiety attached to the solid phase during coupling of the anion exchange moiety. Thus, the density of the anion exchange moieties on the surface of the solid phase can be controlled and adjusted for subsequent application of the solid phase. In particular, the solid phase may comprise a ratio of anion exchange moiety to inert ligand of from about 1:1 to about 1:10, preferably from about 1:2 to about 1:5, more preferably about 1: 3.

In another embodiment, the solid phase does not comprise such inert ligands. According to one embodiment, the solid phase comprises only anion exchange moieties and no other ligands. According to one embodiment, the solid phase comprises a silicon-containing surface, preferably a polysilicic acid surface, derived from silane compounds comprising anion exchange groups and not derived from other silane compounds.

Examples of suitable solid phases, anion exchange groups, functional groups and inert ligands (containing neutral groups N) are described in WO 2010/072834, DE 102008063001 a1 and DE 102008063003, the contents of each of which are incorporated herein by reference.

Preferred embodiments of anion exchange surfaces

According to a particularly preferred embodiment, the anion exchange surface is a surface, preferably a carboxylated surface, comprising anion exchange moieties, preferably comprising amine groups. Preferably, Polyethyleneimine (PEI) is used as an anion exchange moiety to bind the cells from the liquid sample. Preferably, the anion exchange surface is provided in the form of particles, more preferably in the form of magnetic particles. This preferred embodiment of the anion exchange surface will be described in further detail.

Polyethyleneimine (PEI) is a polymer whose molecules are built from ethyleneimine repeating units (also known as aziridines) whose 3-membered rings open during polymerization.

Exemplary PEI molecules are shown below:

hence, PEI is typically a branched molecule constructed from ethyleneimine units bonded through a nitrogen atom. In certain embodiments, PEI is used in the form of a product purchased from Sigma-Aldrich chemical company ("Sigma-Aldrich"), product number 408719(100 mL). The molecule is an ethylenediamine terminated polyethyleneimine and has an average molecular weight of about 800 as determined by Light Scattering (LS) (according to sigma aldrich) and about 600 as determined by Gel Permeation Chromatography (GPC). The molecular weight of ethyleneimine (CH 2NH) is 43, assuming an average molecular weight of 800 for the PEI molecule as reported by sigma-aldrich, which has about 18 units of CH2NH, some of which may be branched. In essence it has about 18 primary (-NH2), secondary (-NHR) or tertiary (-NR2) amine groups (where R is a carbon-containing group bonded to the amine nitrogen through a carbon atom linkage).

The form of PEI suitable for use herein is of course not limited to the product available from sigma-aldrich. PEI is polymeric in nature, allowing for a wide variety of forms, allowing for the degree of polymerization to be at least partially controlled during its synthesis. Thus, many PEI variants with various numbers of repeating units and different amounts of branching are suitable for use in the present invention. For example, it is suitable to have 10-30 CH2CH2NH units, for example 12-24 units, for example 16-20 units. Typically with a range of lengths suitable for cell capture. Additionally, different end caps of ethylenediamine may also be used to prepare PEI variants suitable for use in the present invention. Such endcapping may include, but is not limited to, 1, 2-propanediamine, 1, 3-propanediamine, 1, 2-butanediamine, 1, 3-butanediamine, 1, 4-butanediamine.

PEI molecules suitable for use as the anion exchange moiety in the present invention can be characterized by molecular weight. In particular, suitable PEI molecules have a molecular weight of 600-800 Da. The molecular weight of suitable PEI molecules is measured as 700-900Da when measured by LS and as 500-700Da when measured by GPC.

To provide a surface comprising PEI as anion exchange moiety, PEI is typically immobilized, e.g. bound, to the surface of a solid support, e.g. a particle, preferably a magnetic particle. Particles are typically formed using materials that facilitate the binding of PEI. Exemplary materials from which such particles can be formed include polymeric materials modified to attach ligands. Typically, such solid supports themselves may be derivatized with surface functional groups that readily react with PEI molecules and create chemical bonds between the surface and the PEI. An ideal surface functional group that is often employed is a carboxyl group (-COOH). Exemplary polymeric materials that provide or are modified to provide carboxyl and/or amino groups for attachment of PEI include, for example, polystyrene, latex polymers (e.g., polycarboxylate coated latex), polyacrylamide, polyethylene oxide, polyacrylate, and derivatives thereof. Polymeric materials that can be used to form suitable particles are described in U.S. patent No. 6235313 to Mathiowitz et al. Other materials include glass, silica, agarose, amino-propyl-triethoxysilane (APES) modified materials and the above materials.

During the reaction of PEI molecules with carboxylated particles, such as magnetic particles, all possible amine groups on the PEI molecule, for example one of the 18 possible groups of the sigma-aldrich product mentioned above, are used to react with COOH groups on the surface of the particles to form carbodiimide bonds. The remainder of the total amine groups, for example 17 groups from the sigma-aldrich products described above, may be available for protonation and may thus provide anion exchange functionality. In some embodiments, the synthetic scheme comprises: washing a certain amount of microspheres with carbonate and MES buffer; preparing sulfo-NHS and EDAC; incubation of microspheres with sulfo-NHS and EDAC for 30 min; washing the microspheres with MES and borate buffer; the microspheres are contacted with PEI for 8-10 hours; and rinsing the unbound microsphere PEI. Suitable methods for preparing PEI functionalized particles preferably used in the process of the present invention are described in US2010/0009351, which is incorporated herein by reference.

There are various sources of particles that can be used to bind PEI and used in the methods described herein, for example: magnetic carboxyl modified magnetic beads of salad (part number 3008050250, seradan (Seradyn)), Polysciences BioMag (PB corporation) carboxyl beads, Dynal polymer encapsulated magnetic beads with a carboxyl coating, and Polybead carboxylate modified microspheres available from polytcience (PS corporation), catalog number 09850.

The high density of PEI molecules on the particle surface enables efficient capture of cells in a sample even with a small number of particles.

As mentioned above, the particles are preferably magnetic. Magnetic particles are preferred because their separation from the solution in which they are suspended generally does not require centrifugation. Magnetic particles can be moved by applying a magnetic field, and are therefore suitable for automation. Suitable and preferred particle sizes are described above and these sizes are also applicable to the preferred embodiment wherein PEI groups are used as the anion exchange moiety.

Because the nitrogen atom is trivalent, and because of the conditions of the polymerization reaction, each PEI molecule may have a mixture of primary, secondary, and tertiary amine groups. Thus, polyethylene molecules exhibit a range of pKa values roughly corresponding to those of primary, secondary and tertiary aliphatic amines. Therefore, the pKa of PEI is typically greater than 9.0. Thus, at low pH, PEI is generally positively charged, and can even carry multiple positive charges per molecule due to protonation of amine groups at pH below their pKa, thus enabling strong binding of cells in solution. Thus, the use of PEI functionalized particles is particularly effective for concentrating and thus harvesting cells from a sample containing the cells.

PEI molecules are also advantageous for use as the anion exchange moiety in the present invention because they are resistant to, for example, degradation by lytic enzymes, harsh chemicals such as detergents, and can be heated to temperatures up to 95 ℃. This is particularly advantageous as it enables the anion exchange surface containing PEI as the anion exchange moiety, preferably the PEI functionalized magnetic particles described herein, to remain present in the sample/treatment mixture, even after cell lysis, and during the time that it can remain present during nucleic acid denaturation and hybrid generation and capture. Thus, as shown in the examples, there is no need to separate the PEI-bearing cells as an anion exchange moiety to collect the magnetic particles prior to performing lysis, denaturation, and hybrid capture assays. This is an important advantage, since the elimination of the operating step also makes the method very convenient for the user. As shown in the examples, this embodiment is suitable and works very unexpectedly because PEI itself can act as an inhibitor of enzymatic processes or can capture released nucleic acids. Thus, it was not expected that an anion exchange surface containing PEI groups as anion exchange moieties could be maintained in the sample/treatment mixture during nucleic acid release, denaturation, and hybrid generation and capture, however, this is shown to be possible herein.

Particle suspension

The particles carrying the anion exchange moieties described herein may be provided in the form of a suspension. Preferably, they are contained in an aqueous solution. In a simple embodiment, the particles are provided in water. According to an embodiment, the pH of the suspension containing the particles is 13 or lower, 12 or lower, 11 or lower, 10 or lower, 9 or lower, 8.5 or lower, 8 or lower, 7.5 or lower, 7 or lower, preferably having a pH below 6.5. Preferred pH values may be selected from 3.5-10, 3.75-9, 4-8, 4.25-7, 4.5-6.5, 5-6.25 and 5.5-6.25. According to one embodiment, the solution comprises one or more additives selected from the group consisting of: buffers, particularly biological buffers described herein (e.g., TRIS, MES, or MOPS), detergents, preferably non-ionic detergents (e.g., at a concentration of 2.5% or less, more preferably 1% or less, 0.5% or less, 0.25% or less, or 0.175% or less), and preservatives, such as azides (e.g., at a concentration of 0.5% or less, 0.25% or less, 0.2% or less, 0.1% or less, 0.05% or less). The design of the solution can affect the settling characteristics of the particles. Solutions containing all the aforementioned additives have good sedimentation characteristics and are particularly suitable for particles containing amine groups, in particular magnetic particles functionalized with polyethyleneimine. The solution used to provide the particle suspension is preferably storage stable such that the particle suspension is stored for at least 3 months, at least 6 months, preferably at least 12 months. These characteristics are achieved by the above-described solutions which can be used to provide particle suspension. Suitable buffers to provide particle suspensions are also described in US2010/0009351, which is incorporated herein by reference.

According to one embodiment, the particle suspension comprises particles providing an anion exchange surface, preferably magnetic particles as described above, in a concentration selected from the group consisting of: 1mg/ml to 100mg/ml, 1mg/ml to 75mg/ml, 2mg/ml to 60mg/ml, 2mg/ml to 50mg/ml, 2.5mg/ml to 40mg/ml, 2.5mg/ml to 35mg/ml, 3mg/ml to 30mg/ml, 4mg/ml to 27.5mg/ml, 5mg/ml to 25mg/ml, 7.5mg/ml to 22.5mg/ml, 10mg/ml to 20mg/ml and 12.5mg/ml to 17.5 mg/ml. Good results are achieved at concentrations of 10-50mg/ml, preferably 10-20 mg/ml. Most preferably, the particles are contained in the suspension at a concentration of about 15 mg/ml. Examples of suitable and preferred particle sizes and magnetic particles are as described above.

Cell sample

The cell sample contains cells. The cell may be prokaryotic or eukaryotic. Preferably, the cell is a eukaryotic cell, more preferably the cell is a mammalian cell. According to a preferred embodiment, the cell is a human cell. The cells may be derived, for example, from biological, in particular clinical, samples. Cell samples can be collected from a human, e.g., a patient, using a cell collection device, such as a swab, cervical comb (cervical broom), cervical brush, spatula, disposable swab (floqswab), or similar collection device, or by collecting bodily fluids, such as blood, urine, bodily fluids, semen, and the like. Thus, essentially any sample in which cells are present can be used, including but not limited to: cell suspensions, specimens or cultures containing cells (e.g., cell and tissue cultures); clinical and laboratory biological samples; food and agricultural samples; and forensic samples including semen, hair, blood, skin and saliva samples; cell-containing samples, in particular body samples, such as body fluids and tissues, in particular whole blood, bone marrow aspirate, lymph fluid, urine, amniotic fluid, sperm/semen, bronchial lavage fluid, in vivo secretions, nasal secretions, vaginal secretions, wound secretions or cell-containing samples obtained from the aforementioned body fluids and tissues, obtained from a mammal, preferably a human. Samples can be from any mammal, including humans, and specifically include liquids, solids (e.g., feces) or tissues, as well as liquid and solid foods, feed products and ingredients, such as dairy products, meat and meat by-products, and waste materials. Specifically included are samples taken directly from mammals as well as samples stored in preservatives, including but not limited to: paraffin embedded tissue specimens, cells stored in liquid based cytology media and tissue or cell samples. The cells are contained in a liquid that may be at least partially derived from the biological sample itself (e.g., in the case of blood, or cell culture), or may be partially or completely provided by a collection medium for receiving the cells and/or for receiving a biological sample containing the cells. For example, a cell sample obtained by using a swab or other cell collection device (e.g., a scraper or brush) can be contacted with a collection medium, such as a liquid-based cytology medium. This is particularly preferred when treating epithelial cells, such as cervical cells. According to one embodiment, the cell is an epithelial cell. The corresponding cells may be collected from, for example, a cell culture, or may be obtained from the patient by using a suitable collection device. According to one embodiment, the cell is a cervical cell. The respective cells may be collected from the woman, for example, by using a swab or other suitable collection device (e.g., a spatula or brush). The collected cells are then typically contacted with a liquid-based cytology medium to preserve the cells during transport and/or storage. The term "cell sample" as used herein also includes cells contained in or in contact with a corresponding collection and/or storage medium, in particular cells contained in a liquid-based cytology medium.

In one embodiment, the cell sample comprises at least one fixative. In one embodiment, the sample comprises a cross-linked and/or non-cross-linked fixative. Cross-linking fixatives work by creating chemical bonds between proteins in a sample, thereby causing them to precipitate and fix in the sample. Exemplary crosslinking fixatives include, but are not limited to, formaldehyde and paraformaldehyde. The non-cross-linking fixative does not chemically alter the proteins in the sample; they simply precipitate the proteins in the sample in which they were found. Non-crosslinking fixatives include ethanol, acetone, methanol, and mixtures thereof.

In a preferred embodiment, the cells are contained in a liquid-based cytology medium. Liquid-based cytological media are well known and widely used in the art and, therefore, need not be described in detail herein. Exemplary liquid-based cytology media include, but are not limited to:

(Hologic Corp-Hologic, Inc., Bedford, MA, Bedford, Mass.) (methanol-based liquid-based cytology medium);(Bidi corporation-Becton, Dickinson and Company, Franklin Lakes, N.J., Franklin Lakes of Franklin, N.J.) (liquid based cytology media containing alcohols and aldehydes); m4(Remel), M4RT (Remel), Copan UTM (universal transport medium) and Eagle Minimal Essential Medium (EMEM). The liquid-based cytology medium used preserves the cells and therefore does not induce or does not substantially induce cell lysis. As shown in the examples, a base sample material collected in a liquid-based cytology medium may be analyzed using the methods of the present invention. If desired, a part of the cells can be taken out of the basic sample material beforehand for further useThe purpose is. These cells can be used, for example, for other analytical purposes, such as cytological examinations. According to one embodiment, the cells contained in the sample material are suspended and then processed, for example by vortexing. This is possible if only an aliquot of the base sample material is processed. According to one embodiment, the cell sample is

The pre (pre-quot) samples were used. In that

In pre-use (pre-quot) samples, pairs were collected

The base material in the medium is processed. For example, the cell-containing portion of the base material can be treated using the methods of the present invention. The treatment of the base material is preferred because it avoids the sample preparation step and thus saves the handling steps. According to one embodiment, the cell sample is

Post-use (post-quot) samples.Post-use (post-quot) samples were prepared from the base by a sample preparation procedureSamples are obtained to allow parallel analysis of the collected cells, for example by cytology, such as PAP testing. For example, cells harvested from density gradients, such as cervical cells, are obtained in

And re-suspended in the medium. This enriched cell suspension is referred to in the art as a "post-plot" or "post-gradient" sample. As shown in the examples, these two categoriesThe sample may be treated by the method of the invention. Furthermore, the remaining pre-quot (before use) sample can be processed as shown in the examples.

Contact conditions

In step a), a cell sample is contacted with a surface comprising an anion exchange moiety under conditions suitable to induce binding of the cell to the surface. Binding is mediated by direct interaction between the cell and the surface, particularly between the cell and the anion exchange moiety. Thus, the binding of cells to the surface is not mediated by specific binding partners (such as antibodies) or similar binding molecules. The cells are contacted with the anion exchange surface for a sufficient period of time, such as a period of time sufficient for the cells themselves to bind/attach to the anion exchange surface. Such a period of time should be at least 10 seconds, preferably at least 15 seconds, more preferably at least 20 seconds, and is preferably selected from: at least 30 seconds, at least 1 minute, at least 1.5 minutes, at least 2 minutes, at least 2.5 minutes, at least 3 minutes, at least 4 minutes, at least 5 minutes, or at least 6 minutes. Suitable incubation times can also be determined by the skilled person. As shown in the examples, a very short incubation period has been suitable for rapid binding of cells to the anion exchange surface described herein.

According to one embodiment, an aliquot of the above-described particle suspension is contacted with a sample of cells, wherein the cells are contained in a liquid, preferably the above-described liquid-based cytology medium. According to one embodiment, the volume of the cell sample comprising liquid is selected from: 0.05ml-10ml, 0.1ml-7.5ml, 0.2ml-6ml, 0.25ml-5ml, 0.3ml-4ml, 0.35ml-3.5ml, 0.4ml-3ml and 0.5-2.75 ml. The method of the invention is particularly advantageous in that both small and large volumes of sample can be processed. In addition, cells may be captured from the diluted sample. An important advantage of increasing the sample volume is that the overall sensitivity of the method can be increased. Furthermore, since chemicals are generally not required to adjust the cell binding conditions, in particular to adjust the pH of cell binding, the entire process volume of the robotic system can be essentially used as the sample volume. The selected sample volume is contacted with an aliquot of the particle suspension. Suitable aliquot volumes of particle suspensions may be selected from, for example, 5. mu.l to 150. mu.l, 7.5. mu.l to 125. mu.l, 10. mu.l to 100. mu.l, 15. mu.l to 85. mu.l, 20. mu.l to 75. mu.l, 25. mu.l to 65. mu.l, 30. mu.l to 55. mu.l and 35. mu.l to 50. mu.l. Preferably, the particle suspension comprises said particles, preferably magnetic particles, in a concentration selected from the range of the particle suspension described above. Robotic systems are easier to handle larger volume aliquots of at least 15 μ L, at least 20 μ L, at least 25 μ L, preferably at least 30 μ L, and are therefore preferred. The particle suspension and the sample may be contacted in any order. For example, a corresponding sample providing the desired amount of particle suspension may be provided in a container, and a sample added to the particle suspension, or vice versa. The resulting mixture comprising the sample and the particle suspension preferably comprises particles at a concentration selected from the group consisting of: 50-2000. mu.g/ml, 75-1750. mu.g/ml, 100-1500. mu.g/ml, 125-1250. mu.g/ml, 140-1200. mu.g/ml, 150-1150. mu.g/ml and 165-1100. mu.g/ml. These concentrations are preferred when particles, preferably magnetic particles, having an average size of 5 μm or less, preferably 3 μm or less, preferably a size of 500nm to 2 μm, preferably 800nm to 1.5 μm are used. Most preferably, the average size of the magnetic particles is about 1 μm. As mentioned above, preferably polyethyleneimine functionalised magnetic particles are used.

As mentioned above, in a preferred embodiment, the cell sample comprises epithelial cells, such as cervical cells collected in a liquid-based cytology medium. If the treated cell sample contains a liquid-based cytology medium containing a cross-linking fixative (e.g.,sample), the mixture containing the cell sample and the particle suspension preferably comprises the above particles, preferably magnetic particles, in the following concentrations: 300. mu.g/ml-2000. mu.g/ml, 400. mu.g/ml-1500. mu.g/ml and 500. mu.g/ml-1250. mu.g/ml. For example, a sample volume of 0.5ml to 1ml (e.g.,

sample) may be contacted with 35. mu.L to 50. mu.L of the above-described particle suspension, preferably containing particles at a concentration of 10 to 50mg/ml, preferably 10 to 20mg/ml, especially about 15 mg/ml. Corresponding granulesThe concentrations are also suitable for use with liquid-based cytology media containing higher concentrations of cells. If the liquid-based cytology medium does not include a cross-linking fixative in the treated cell sample (e.g.,sample), the mixture comprising the sample and the particle suspension preferably comprises the above-mentioned particles, preferably magnetic particles, in the following concentrations: 100 μ g/ml to 750 μ g/ml, 125 μ g/ml to 600 μ g/ml, 150 μ g/ml to 500 μ g/ml and 165 μ g/ml to 400 μ g/ml. For example, a cell sample having a volume of 2ml to 3ml (e.g.,sample) may be contacted with 35. mu.L to 50. mu.L of the above-described particle suspension, preferably containing particles at a concentration of 10 to 20mg/ml, in particular 15 mg/ml. The corresponding particle concentration is also suitable for the utilization of liquid-based cytology media with lower cell concentrations. As mentioned above, preferably polyethyleneimine functionalised magnetic particles are used. The particles may also comprise carboxyl groups on their surface. Preferably, the magnetic particles have an average size of 5 μm or less, preferably 3 μm or less, preferably an average size in the range 750nm to 2 μm, preferably 800nm to 1.5 μm. Most preferably, the average size of the magnetic particles is about 1 μm.

As shown in the examples, the use of anion exchange surface energy binds cells under various conditions according to the teachings described herein. This is particularly advantageous because it leads to the fact that the method of the invention is reliable and not prone to errors. As shown in the examples, many contaminants contained in cell samples, particularly cervical cell samples, do not significantly interfere with the performance of cell binding. This is an important advantage in the field of diagnostics, in particular the diagnosis of HPV, where cell samples, such as cervical samples, may contain contaminants.

Furthermore, as shown in the examples, binding of cells to anion exchange surfaces can occur at different pH values. The appropriate pH range also depends on the pKa of the anion exchange group of the anion exchange moiety, since the anion exchange group should be positively charged to ensure that the cells haveAnd (4) effect combination. Thus, according to one embodiment, the binding occurs at a pH value where the anion exchange groups of the anion exchange moiety are positively charged. According to one embodiment, the cell binding occurs in step a), at a pH value selected from the group consisting of: a pH of 9.5 or less, a pH of 9 or less, a pH of 8.75 or less, a pH of 8.5 or less, a pH of 8.25 or less, a pH of 8 or less, a pH of 7.75 or less, a pH of 7.5 or less, a pH of 7.25 or less, a pH of 7 or less, a pH of 6.75 or less, a pH of 6.5 or less, a pH of 6 or less. Preferably, cell binding occurs at a pH value selected from the group consisting of: 3 to 8.5, 3.5 to 8.0, 3.5 to 7.75, 3.5 to 7.5, 3.5 to 7.25, 3.75 to 7, or 4 to 6.5. As shown in the examples, preferably binding occurs at a pH of 8.5 or less, preferably 8 or less, more preferably 7.5 or less, especially at a neutral or acidic pH of 7 or less or 6.5 or less, the binding efficiency of the cells to the anion exchange surface is increased and binding is very rapid. The stated pH values and ranges are particularly preferred when the surface is functionalized with an amine, such as polyethyleneimine. It is a particular advantage of the method of the invention that the binding of the cells to the anion exchange surface can take place under various conditions, in particular at various pH values. Thereby, the method of the invention can be applied to a large number of cell samples without the need for special adjustments of the liquid containing the cells, in particular pH adjustments. For example, epithelial cells, such as cervical cells, are typically collected/stored in a collection/storage medium. Depending on the collection/preservation medium used, the medium may have a pH of from moderate to slightly basic to acidic. Thus, if the cells are contained in a collection medium, such as a liquid-based cytology medium, the above pH values are typically provided or present. For example, the pH of the standard collection medium SURPATH is about 7, while the standard collection medium SURPATHThe pH of (1) is 4 to 5. As shown in the examples, the method of the invention can be used in combination with these two collection media, even if their pH values are very different. When cells contained in the respective collection media as described herein contact the anion exchange surface, the cells are contacted with the anion exchange surfaceCells bind directly to the surface with fast kinetics. Therefore, when such a sample is processed, no special adjustment of the binding conditions is required using the technique of the present invention. Cells can be bound to the anion exchange surface without the need to achieve a specific pH range by adding a binding buffer to the cell sample or by adjusting the pH. This is an important advantage because it saves processing steps, saves costs, makes the method suitable for many different types of cell samples and reduces the risk of processing errors leading to distortion of the results. Thus, according to one embodiment, binding conditions, in particular pH, are not adjusted, and the cell is bound by simply contacting the anion exchange surface, preferably the magnetic particles comprising the anion exchange moiety, with the cell sample followed by incubation.

However, as shown in the examples, the bonding can also take place in the presence of additives, such as alcohols. Thus, if desired, corresponding additives, for example branched or straight-chain alcohols having from 1 to 5 carbon atoms, such as isopropanol, or mixtures of the individual alcohols, can be added in the combining step. However, the addition of corresponding additives is not necessary, as the examples show, the binding of the cells to the anion exchange surface is not necessarily improved thereby. Therefore, for simplicity, it is preferred that no alcohol or other additives be added to the cell sample to support binding of the cells to the anion exchange surface. As described above and demonstrated in the examples, it is preferred within the scope of the present invention to provide the anion exchange surface in the form of a suspension, in particular the magnetic particles comprising the anion exchange moiety. Thus in the combining step there is a liquid present for providing a suspension of particles. If, for example, a cell sample with a relatively alkaline property is to be treated, this liquid can be used for a specific pH adjustment. By suspending the anion exchange particles using an acidic suspension medium, the pH of the combined mixture containing the particles and the cell sample can be lowered without increasing the processing steps and without the need for separate addition of a binding agent.

After step a), the cells are bound to a surface comprising anion exchange groups.

Step B)

In step b), the surface to which the cells are bound is separated from the rest of the sample, whereby the cells are collected. In this case, different modes of operation can be used for separating the cell-bound surface from the remaining sample, depending also on the solid phase used. Non-limiting examples are as follows.

For example, if a container is utilized wherein the interior walls of the container are at least partially functionalized with an anion exchange moiety as described herein, the remaining sample can be discarded by decantation or can be removed by suction or the like. The bound cells are maintained in association with the interior surface of the container by the anion exchange moiety. The respective separation step may be performed using a robotic system to separate the remaining samples.

According to a preferred embodiment, particles comprising anion exchange moieties, in particular particles functionalized on their surface with polyethyleneimine, are used to provide anion exchange surfaces. If the particles are non-magnetic, they may be collected by filtration or sedimentation, for example with the aid of centrifugation according to one embodiment. The use of magnetic particles is preferred because magnetic particles containing bound cells can be simply treated by means of a magnetic field, for example using a permanent magnet. This embodiment is preferred because it is compatible with existing robotic systems capable of handling magnetic particles. Here, there are different robotic systems in the prior art that can be used with the present invention to process cell-bound magnetic particles. According to one embodiment, the magnetic particles are collected at the bottom or side of the reaction vessel, while the remaining liquid sample is removed from the reaction vessel, leaving the collected cell-bound magnetic particles. The remaining sample can be removed by decantation or aspiration. Such systems are well known in the art and need not be described in detail herein.

In known alternative systems for handling magnetic particles, a magnet, typically covered with a lid or housing, is dropped into a reaction vessel to collect the magnetic particles. The magnetic particles carrying the bound cells may then be transferred, for example, to a new reaction vessel, for example, a vessel containing a resuspension, preferably a denaturing composition, as described below. Since corresponding systems are well known in the art, they are also commercially available (e.g., commercially available)

QIAGEN-QIAGEN), which need not be described in detail herein.

In a further alternative system known for handling magnetic particles, a sample containing magnetic particles may be drawn into a pipette tip where they may be collected by placing a magnet in a position, for example, to one side of the pipette tip. The remaining sample is then released from the pipette tip, while the collected magnetic particles carrying the bound cells remain at the pipette tip. The collected magnetic particles may then be further processed. Such systems are also well known in the art and are also commercially available (e.g., BioRobot EZ1, qiagen) and, therefore, need not be described in any detail herein.

It is preferred within the scope of the present invention to contact the bound cells with the liquid composition after step b. This embodiment has the advantage that it may especially support cell collection if magnetic particles are used, in particular if a robotic system is used, throwing a magnet into the reaction vessel to collect the magnetic particles. By contacting the collected cells, still bound to the magnetic particles, with the liquid composition, it can be ensured in this embodiment that the particles containing bound cells are effectively separated from the magnet and redispersed in the liquid composition. However, there are additional general advantages to contacting the collected cells with a liquid composition when using other magnetic separation systems or other anion exchange surfaces as described herein. The liquid composition can be used, inter alia, to prepare collected cells for use in hybrid capture assays. Thus, the liquid composition is compatible with subsequent downstream processing, particularly the hybrid capture assay performed in steps d) and e). The liquid composition may be added to the collected cells bound to the anion exchange surface, e.g. to the magnetic particles carrying the bound cells, or vice versa. According to one embodiment, contacting the anion exchange surface carrying the bound cells with a liquid composition causes at least a portion of the collected cells to be released, thereby eluting from the anion exchange surface. The anion exchange surface can then be separated from the released cells, if desired. Any separation means may be used herein, suitable means include, but are not limited to: the liquid composition containing the released cells is collected, for example by aspiration or, if magnetic particles are used, a magnetic field can be used to collect and separate the magnetic particles from the remaining liquid composition containing the released cells. However, as shown in the examples, it is not necessary to remove, separate the anion exchange surface before steps c) and d), which is a particular advantage of the present invention, which again eliminates the treatment step. The cells may even maintain binding to the anion exchange surface as long as nucleic acid is released therefrom (see step c).

Step C)

In step c), the nucleic acids are released from the collected cells, preferably also denatured. There may be several options here, suitable and preferred embodiments of which will be described below.

According to a preferred embodiment, the liquid composition is contacted with the collected cells as described in the preceding paragraph. As noted above, the liquid composition may assist in this release, thereby eluting the cells from the anion exchange surface (although this is not required). Preferably, however, the liquid composition is a composition that facilitates the release of nucleic acids from the cells in step c).

According to one embodiment, the collected cells are contacted with a liquid composition comprising a chaotropic agent. Any chaotropic agent that causes protein or nucleic acid disorders may be used for this purpose, by way of example and not limitation, altering the secondary, tertiary or quaternary structure of proteins or nucleic acids. Preferably, chaotropic salts (chaotropic salts) are used. The chaotropic salt preferably comprises guanidine, thiocyanate, isothiocyanate, perchlorate, trichloroacetate and/or trifluoroacetate as chaotropic ion. Preferably, the chaotropic agent is selected from the group consisting of: guanidine (guanidinium) salts, guanidine hydrochloride, guanidine thiocyanate, guanidine isothiocyanate, sodium thiocyanate, sodium iodide, sodium perchlorate, sodium trichloroacetate, sodium trifluoroacetate, and urea. Mixtures of chaotropic agents may also be used. Preferably, a guanidinium salt, such as guanidinium hydrochloride, guanidinium thiocyanate or guanidinium isothiocyanate is used as chaotropic agent in the composition assisting the release of nucleic acids in step c). The liquid composition may comprise a chaotropic agent, preferably a chaotropic salt as described above, in a concentration range selected from the group consisting of: from about 0.1M to the maximum saturation limit, from about 0.2M to about 5M, from about 0.3M to about 4M, from about 0.4M to about 3M, from about 0.5M to about 2.5M, from about 0.6M to about 2M, from about 0.6M to about 1.5M, and from about 0.6M to about 1M. Preferably, the liquid composition is a lysis solution, such as a lysis buffer.

According to one embodiment, the composition comprises a chelating agent, preferably EDTA. A chelating agent is an organic compound capable of forming coordinate bonds between two or more atoms of the organic compound and a metal. Suitable chelating agents include, but are not limited to, diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), ethyleneglycoltetraacetic acid (EGTA), and N, N-bis (carboxymethyl) glycine (NTA). According to a preferred embodiment, EDTA is used. As used herein, the term "EDTA" especially denotes the EDTA moiety of an EDTA compound, e.g., K₂EDTA、K₃EDTA or Na₂EDTA。

According to one embodiment, the composition comprises a detergent. The detergent may be nonionic, ionic, anionic, cationic or zwitterionic.

In addition, the composition may contain a preservative such as sodium azide. In addition, the composition may comprise a buffering agent. Preferably, the composition comprises a biological buffer, such as HEPES, MES, MOPS, TRIS, BIS-TRIS propane and other biological buffers. Preferably, Tris buffer is used.

In step c), the released nucleic acids are also preferably denatured. This can be achieved, for example, by the addition of a denaturing agent, such as an alkali, and/or heat, as described below. In particular, if the target nucleic acid is a double stranded molecule, e.g.a DNA molecule, it is preferred to convert the double stranded target nucleic acid into a single stranded target nucleic acid molecule in step c) so that the nucleic acid can be hybridized in step d).

Preferably, the liquid composition that facilitates or effectuates release of nucleic acids from cells has an alkaline pH that effectuates or supports denaturation of the released nucleic acids. Furthermore, it was found that the use of a liquid composition having an alkaline pH also facilitates the release of bound cells from the anion exchange surface due to alkaline pH induced charge transfer and thereby elution. According to one embodiment, the pH of the liquid composition is selected from: a pH of 10 or more, a pH of 11 or more, a pH of 11.5 or more, a pH of 12 or more, a pH of 12.5 or more, a pH of 12.75 or more, a pH of 13 or more and a pH of 13.25 or more. The high alkaline pH supports the release of nucleic acids, and in addition, denatures the released nucleic acids, thereby preparing the nucleic acids for step d). This embodiment is particularly preferred if the target nucleic acid is DNA, since such an alkaline pH will both cleave and degrade most of the internal RNA in the sample. Preferably, the heating supports denaturation, as described below. In addition, the alkali treatment can disrupt the interaction between the peptide and the nucleic acid to improve the accessibility of the target nucleic acid to the degraded protein. In addition, the alkaline-treated protein is effective in homogenizing the sample to ensure reproducibility of the results of a given sample analysis. It may also reduce the viscosity of the sample to improve kinetics, homogenize the sample, and reduce background by disrupting any endogenous single-stranded RNA nucleic acids, DNA-RNA hybrids, or RNA-RNA hybrids in the sample. This also helps to inactivate enzymes that may be present in the sample, such as rnases and dnases. It will be appreciated by those skilled in the art that if RNA is the target nucleic acid (as opposed to DNA), a different reagent may be preferred. To establish the above-mentioned basic pH, a base, preferably a chemical base, such as sodium hydroxide or potassium hydroxide, may be added, each being comprised in the liquid composition.

The use of a strongly basic liquid composition as described above is particularly suitable if the target nucleic acid is DNA. If the target nucleic acid is RNA, milder conditions are preferred in order to maintain the integrity of the RNA. For example, the pH of the liquid composition may be 7.5-10, 8-9.5 or 8.5-9, particularly if an anion exchange surface is used which is capable of releasing cells at a pH of 8 or lower, preferably 7 or lower.

The liquid composition to be contacted with the collected cells may be provided by one composition, such as one solution, or may be prepared by contacting the cells with two or more separate compositions. According to one embodiment, the collected cells are contacted with two or more discrete compositions, thereby providing the above-described release and denaturing conditions. According to one embodiment, two or more compositions are first mixed to provide a liquid composition as described above, and the composition is then contacted with an anion exchange surface (preferably magnetic particles) to which cells are bound. According to an embodiment, the first composition comprises a chaotropic agent and optionally other ingredients as described above (e.g. composition STM may be used as the first composition, see examples), and the separate second composition contains a denaturant (e.g. DNR as the second composition, see examples). Preferably, the second composition is an alkaline solution. Any base that enables the first and second compositions to be mixed to produce a liquid composition having the pH range described above is suitable. Suitable concentrations of the base include about 1.0N to about 2.0N or about 1.25N to about 1.75N. However, higher concentrations of alkali solutions may also be used to achieve a pH in the above pH range. Suitable bases include, but are not limited to, NaOH and KOH. Mixing the two (or more) compositions together provides a liquid composition that facilitates release and denaturation of the nucleic acid, thereby providing the conditions described above, and in particular achieving the alkaline pH values described above. Preferably, the liquid composition is prepared by mixing two or more separate compositions to achieve the preferred conditions described above, with the addition of the denaturant described above being especially preferred. According to one embodiment, a second composition comprising a denaturant is first provided, and the first composition comprising a chaotropic agent is added to the second composition to provide the liquid composition described above. The liquid composition obtained accordingly is then preferably contacted with the collected cells bound to the anion exchange moiety.

According to one embodiment, the surface is provided by magnetic particles, and the collected cells bound to the magnetic particles are contacted with a liquid composition as described above in an amount selected from the group consisting of: 25. mu.l-500. mu.l, 30. mu.l-400. mu.l, 35. mu.l-300. mu.l, 40. mu.l-250. mu.l, 50. mu.l-200. mu.l, 60. mu.l-175. mu.l, 70. mu.l-150. mu.l, 80. mu.l-125. mu.l and 85. mu.l-100. mu.l. According to one embodiment, the volume of liquid composition added is such that the concentration of particles after resuspension is selected from the group consisting of 2000. mu.g/ml-15000. mu.g/ml, 2500. mu.g/ml-12500. mu.g/ml, 3000. mu.g/ml-10000. mu.g/ml, 3500. mu.g/ml-9500. mu.g/ml, 4000. mu.g/ml-9000. mu.g/ml, 4500. mu.g/ml-8750. mu.g/ml and 5000. mu.g/ml-8500. mu.g/ml. Particularly good results are obtained when the magnetic particles with bound cells are resuspended in a volume of liquid composition such that 1mg or less of particles are present in a volume of 150. mu.l, preferably 125. mu.l, more preferably 100. mu.l or less. As shown in the examples, volumes of the liquid composition, in particular volumes of more than 60. mu.l, more than 70. mu.l, more preferably more than 80. mu.l, provide particularly good results in subsequent hybridization capture assays. This is especially (advantageous) if the magnetic particles are not removed before carrying out step d). For liquid compositions, the range of 85. mu.l to 100. mu.l is most preferred.

Instead of or preferably in addition to the above-mentioned denaturing agents, other methods of denaturation can be used, for example a heating step, for example heating the sample to at least 80 ℃ or at least 95 ℃ to separate the nucleic acid strands. It is preferable to add an alkaline denaturing agent, which may be contained in the above-mentioned liquid composition, while performing a heating step to effectively denature the released nucleic acid.

According to one embodiment, after the cell has been contacted with the above-mentioned liquid composition, preferably an alkaline liquid composition, the resulting mixture is heated to promote denaturation of the nucleic acid. Preferably, the mixture is heated to at least 55 ℃, preferably at least 60 ℃. Suitable temperature ranges include 55 ℃ to 90 ℃, preferably 60 ℃ to 85 ℃, more preferably 65 ℃ to 80 ℃. Preferably, the heating is for at least 30 minutes, preferably at least 35 minutes, more preferably at least 40 minutes. Suitable time periods may be selected from: 30 minutes to 150 minutes, 35 minutes to 130 minutes, 40 minutes to 120 minutes and 45 minutes to 100 minutes. The time and temperature conditions should provide for efficient denaturation of the nucleic acid within an acceptable amount of time such that the target nucleic acid is under suitable conditions for performing step d). Suitable time periods also depend on the sample being treated. For example, when treating cell-containing samples containing specific fixative agents, e.g.

For samples, longer incubation times of 90 minutes (or longer if desired) at a temperature of at least 60 ℃, preferably about 65 ℃ are preferred. When treating cell-containing samples not containing cross-linking fixative, e.g.

For samples, a shorter incubation time, e.g. 45 minutes (or longer if desired) at a temperature of at least 60 ℃, preferably about 65 ℃ is sufficient. Suitable time periods may also be determined by the skilled person. One of ordinary skill in the art will readily appreciate that a tradeoff can be made between longer incubation times at lower temperatures or shorter incubation times at higher temperatures to provide similar effects to those described herein. The release of nucleic acids can also be facilitated by shaking. For example, samples treated with the above-described liquid compositions can be mixed by hand mixing or mechanical agitation at about 800rpm, 900rpm, about 1000rpm, about 600 to about 1000rpm, about 600 and 1200 rpm.

According to one embodiment, a sample mixture comprising a liquid composition, cells and optionally an anion exchange surface, e.g. magnetic particles, or an aliquot of said mixture, is transferred to a new container, preferably a multi-well device, such as a 96-well plate, and then heated. This embodiment is advantageous because it can be easily integrated into existing hybridization capture assay workflows (work-flows) and also into automated processing systems where the corresponding porous devices are routinely processed, thus allowing the use of existing equipment.

After carrying out step c), a sample is obtained which contains the released and preferably also denatured nucleic acids. If the magnetic particles are not isolated before or during step c), the sample optionally also contains anion exchange surfaces, e.g. magnetic particles, which is preferred for safe handling steps.

The sample obtained after performing step c) may be stored at, for example, 4 ℃ or below, and then steps d) and e) are performed.

Step D) and step E)

In step d), hybrids are generated between the target nucleic acid and the probe specific for the target nucleic acid. Preferably, a hybrid capture assay is performed, the hybrid preferably being an RNA/DNA hybrid. As mentioned before, a corresponding separation is possible before step d) without removing the anion exchange surface, which is preferably provided by magnetic particles comprising an anion exchange moiety, preferably PEI. It is very surprising that the anion exchange surface can be maintained during step d), since it is known that nucleic acids are bound to the anion exchange surface. Therefore, there is a concern that the released nucleic acids, nucleic acid probes, and/or hybrids can bind to the anion exchange surface and thus are not available for hybridization and capture. However, as shown in the examples, it is possible that the anion exchange surface can remain present during the generation and capture of the hybrid, particularly if a PEI functionalized surface is employed as the anion exchange surface. This is particularly unexpected because PEI is also known to interfere with enzyme activity and amplification reactions.

Suitable, non-limiting embodiments for performing steps d) and e) are described below.

According to one embodiment, the process of the invention comprises the following steps d) and e):

step d):

-contacting the released and denatured nucleic acid containing sample with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single-stranded target nucleic acid molecules to form double-stranded nucleic acid hybrids;

step e):

-detecting the presence or absence of a double-stranded nucleic acid hybrid.

Preferably, the process of the invention comprises the following steps d) and e):

step d):

-contacting the sample containing the released and denatured nucleic acids and magnetic particles for binding to cells with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single stranded target nucleic acid molecules to form double stranded nucleic acid hybrids;

step e):

-detecting the presence or absence of a double-stranded nucleic acid hybrid.

As described above, the magnetic particles for binding cells preferably contain PEI on the surface thereof.

Preferably, the process of the invention comprises the following steps d) and e):

step d):

-contacting the released and denatured nucleic acid containing sample with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single-stranded target nucleic acid molecules to form double-stranded nucleic acid hybrids;

-capturing the double stranded nucleic acid hybrid;

-optionally separating the double-stranded nucleic acid hybrid from unbound nucleic acids;

step e):

-detecting the presence or absence of a double-stranded nucleic acid hybrid.

Preferably, the process of the invention comprises the following steps d) and e):

step d):

-contacting the sample containing the released and denatured nucleic acids and magnetic particles for binding to cells with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single stranded target nucleic acid molecules to form double stranded nucleic acid hybrids;

-capturing the double stranded nucleic acid hybrid;

-optionally separating the double stranded nucleic acid hybrid from unbound nucleic acids, thereby also removing at least a portion of the magnetic particles;

step e):

-detecting the presence or absence of a double-stranded nucleic acid hybrid.

As described above, the magnetic particles for binding cells preferably contain PEI on the surface thereof.

According to one embodiment, the process of the invention comprises the following steps d) and e):

step d):

-contacting the released and denatured nucleic acid containing nucleic acid with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single-stranded target nucleic acid molecules to form double-stranded nucleic acid hybrids;

-capturing the double-stranded nucleic acid hybrid with a first binding agent that binds to the double-stranded nucleic acid hybrid, thereby forming a double-stranded nucleic acid hybrid/first binding agent complex;

-separating the double stranded nucleic acid hybrid/first binding agent complex from unbound nucleic acid;

-binding the complex to a further binding agent labelled with a detectable label to form a double stranded nucleic acid hybrid/first binding agent/labelled binding agent complex;

-optionally washing the double stranded nucleic acid hybrid/first binding agent/labelled binding agent complex;

step e):

-detecting the presence or absence of the label of the other binding agent, thereby indicating the presence or absence of the target nucleic acid.

According to one embodiment, the process of the invention comprises the following steps d) and e):

step d):

-contacting the sample containing the released and denatured nucleic acids and magnetic particles for binding to cells with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single stranded target nucleic acid molecules to form double stranded nucleic acid hybrids;

-capturing the double-stranded nucleic acid hybrid with a first binding agent that binds to the double-stranded nucleic acid hybrid, thereby forming a double-stranded nucleic acid hybrid/first binding agent complex;

-separating the double stranded nucleic acid hybrid/first binding agent complex from unbound nucleic acids, thereby also removing at least a portion of the magnetic particles;

-binding the complex to a further binding agent labelled with a detectable label to form a double stranded nucleic acid hybrid/first binding agent/labelled binding agent complex;

-washing the double stranded nucleic acid hybrid/first binding agent/labelled binding agent complex, wherein said washing removes remaining magnetic particles, if still present;

step e):

-detecting the presence or absence of the label of the other binding agent, thereby indicating the presence or absence of the target nucleic acid.

As described above, the magnetic particles for binding cells preferably contain PEI on the surface thereof.

According to one embodiment, the process of the invention comprises the following steps d) and e):

step d):

-contacting the released and denatured nucleic acid containing nucleic acid with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single-stranded target nucleic acid molecules to form double-stranded nucleic acid hybrids;

-capturing the double-stranded nucleic acid hybrids on a solid support coated with a first binding agent to which the double-stranded nucleic acid hybrids are bound, thereby forming double-stranded nucleic acid hybrid/solid support complexes;

-separating the double stranded nucleic acid hybrid/solid support complex from unbound nucleic acids;

-binding the complex to another binding agent labelled with a detectable label to form a double stranded nucleic acid hybrid/solid support/labelled binding agent complex;

-optionally washing the double stranded nucleic acid hybrid/solid support/labelled binding agent complex;

step e):

-detecting the presence or absence of the label of the other binding agent, thereby indicating the presence or absence of the target nucleic acid.

According to one embodiment, the process of the invention comprises the following steps d) and e):

step d):

-contacting the sample containing the released and denatured nucleic acids and magnetic particles for binding to cells with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single stranded target nucleic acid molecules to form double stranded nucleic acid hybrids;

-capturing said double stranded nucleic acid hybrids on a solid support coated with a first binding agent, said first binding agent binding the double stranded nucleic acid hybrids, thereby forming a double stranded nucleic acid hybrid/solid support complex;

-separating the double stranded nucleic acid hybrid/solid support complex from unbound nucleic acids, thereby also removing at least a portion of the magnetic particles;

-binding the complex to another binding agent labelled with a detectable label to form a double stranded nucleic acid hybrid/solid support/labelled binding agent complex;

-washing the double-stranded nucleic acid hybrid/solid support/labelled binding agent complex with a washing buffer, wherein said washing removes remaining magnetic particles, if still present;

step e):

-detecting the presence or absence of the label of the other binding agent, thereby indicating the presence or absence of the target nucleic acid.

As described above, the magnetic particles for binding cells preferably contain PEI on the surface thereof.

Suitable and preferred embodiments and aspects of steps d) and e) will also be described below:

probes and hybridization conditions

After the release and denaturation of the nucleic acid that occurs in step c) above, the denatured target nucleic acid is contacted with one or more probes under conditions suitable for hybridization of the one or more probes to the target nucleic acid to form a double-stranded nucleic acid hybrid. The probe is preferably a polynucleotide probe. The probe may be full length, truncated or synthetic DNA or full length, truncated or synthetic RNA. In addition, probes comprising RNA and DNA nucleotides or comprising modified nucleotides and/or nucleotide analogs may be used as long as hybrids can be formed. If the target nucleic acid is DNA, the preferred probe is RNA, if the target nucleic acid is RNA, the preferred probe is DNA. Thus, RNA/DNA hybrids are preferably formed. The probes are designed to hybridize or bind to a target nucleic acid molecule. In one aspect, the probes are capable of hybridizing or binding to HPV and HPV high-risk variants. In additional aspects, the probes are specific for HPV and HPV high-risk variants. The High Risk (HR) detector may comprise probes for the following high risk HPV types: 16. 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68, and 82.

The amount of probe used may vary, from about 7.5ng to about 60ng per HPV type per assay, or from about 20ng to about 45ng per HPV type per assay, or about 30ng of probe per HPV type per assay. Thus, in one aspect, the HR probe consists of, or consists essentially of, one or more probes for the following high risk HPV types: 16. 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68 and 82, or consists essentially of one or more probes for the following low risk HPV types: 6. 11, 40, 43,53, 61, 67, 69, 70, 71, 72, 81 and 83. The RNA probe can be a short synthetic RNA probe that specifically binds only to the target nucleic acid molecule.

In a non-limiting aspect, one or more probes used can hybridize to or bind to a target nucleic acid molecule that is at least 70%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identical to an HPV-related nucleic acid molecule, a genetic variant of HPV, HPV DNA of a high-risk HPV type, or HPV RNA of a high-risk HPV type, or any low-risk HPV type, 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68, and 82, and 6, 11, 40, 43,53, 61, 67, 69, 70, 71, 72, 81, and 83. In another aspect, the one or more probes used are complementary to HPV, genetic variants of HPV, HPV DNA of high-risk HPV types, HPV RNA of high-risk HPV types, or any high-risk HPV type, or any low-risk HPV type, the high-risk HPV types being 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68 and 82, the low-risk HPV types being 6, 11, 40, 43,53, 61, 67, 69, 70, 71, 72, 81 and 83. DNA or RNA fragments of the target nucleic acid may also be used.

According to one embodiment, if denaturation is performed under alkaline conditions, the denatured sample is neutralized prior to or during addition of the probe. According to one embodiment, one or more probes are diluted in a probe diluent that also serves as a neutralization hybridization buffer. This embodiment is advantageous in order to neutralize the alkaline pH values used for releasing and denaturing the nucleic acids in step c). The probe diluent used for DNA or RNA probes varies due to the different requirements required for DNA and RNA stability. For example, if the probe is RNA, it is preferred to neutralize the sample before adding one or more probes, or, alternatively, to add both the RNA probe and a neutralizing agent (probe diluent) to the sample, because a strongly alkaline pH can destroy the RNA. The probe diluent can be used to solubilize and dilute the probe and also to facilitate returning the sample to about neutral or slightly alkaline pH, e.g., about pH 6 to about pH 9, preferably 6.5 to 8, more preferably 6.5 to about 7.5, to provide a more favorable environment for hybridization. The base-treated sample can be neutralized with a sufficient volume of probe diluent, e.g., half the volume of the sample.

In one aspect, the probe diluent comprises a buffer, polyacrylic acid, NaOH, and sodium azide. The probe diluent may comprise acetic acid. In one aspect, the probe diluent comprises 2.2M BES (N, N-bis (2-hydroxyethyl) -2-aminoethanesulfonic acid), 2.6% polyacrylic acid (PAA), 0.7N NaOH, and 0.05% sodium azide. The probe diluent may comprise about 1.2M to about 2.6MBES, about 1.5M to about 2.5M BES, about 1.75M to 2.25M BES, about 2M to 2.4M BES, or about 2.2M BES, and any number within the stated range. In one aspect, the probe diluent may comprise about 2% to about 3.0% PAA, and any number within the stated range. In another aspect, the PAA concentration is about 2.2% to about 2.7%. In yet another aspect, the PAA concentration is about 2.6%. In a further aspect, the probe diluent can comprise about 0.6N to about 0.8N NaOH, e.g., about 0.7N NaOH. The NaOH concentration generally increases with increasing BES usage.

For large probes, a heated base solution may be added to the sample, then probe diluent may be added to the sample at room temperature, and then the sample is heated. This process can suppress the formation of secondary structures. Binding agents (e.g., antibodies) readily bind to structures having secondary structures. When non-full length probes are used, such as truncated or synthetic probes, it may not be necessary to heat the solution or sample, as there is no secondary structure problem. In one aspect, the sample is not heated when used in conjunction with a truncated or synthetic probe. After treatment with the denaturing reagent, an aliquot of neutralization buffer (in one aspect a probe diluent with one or more probes dissolved therein) can be added to the sample under appropriate conditions to allow hybridization or binding of the probes to the target nucleic acids. The neutralization buffer may comprise a buffer salt. In one aspect, the neutralization buffer does not comprise more than one buffer salt. The hybridization conditions are sufficient to allow the one or more polynucleotide probes to anneal to the corresponding complementary nucleic acid sequence (if present) in the sample, thereby forming a double-stranded nucleic acid hybrid.

Hybridization conditions appropriate to the particular probe and diluent used are employed. For example, the probe and sample nucleic acid can be incubated for a hybridization time sufficient to allow the one or more polynucleotide probes to anneal to the corresponding complementary target nucleic acid sequence, preferably at least about 5 to about 120 minutes, about 10 to about 100 minutes, about 20 to about 80 minutes, or about 30 minutes to about 60 minutes, and any number within the stated range. Hybridization conditions may include a hybridization temperature of at least about 55 ℃, at least about 60 ℃, preferably from about 60 ℃ to about 75 ℃, preferably from 65 ℃ to about 70 ℃, and any number within the stated range. For a given target nucleic acid and a given probe, one of ordinary skill in the art will readily be able to determine the desired hybridization conditions and hybridization times by routine experimentation. One of ordinary skill in the art will further appreciate that the time and temperature of hybridization must be optimized relative to each other. Stringent hybridization conditions can be controlled by increasing the temperature, increasing the ionic conditions above 0.5M (e.g., sodium chloride), or decreasing the concentration of PAA, but are not limited thereto. As a non-limiting example, stringent hybridization conditions can include hybridization reactions performed at elevated temperatures, e.g., at least about 65 ℃.

Capture

After one or more probes hybridize to a target nucleic acid molecule and form a double-stranded nucleic acid hybrid, the hybrid is captured by a molecule that binds to the formed double-stranded nucleic acid hybrid. Such molecules are referred to herein as first binders or anti-hybrid binders. Thereby forming a double-stranded nucleic acid hybrid/first binding agent complex. Specific binding agents for double-stranded nucleic acid hybrids include, but are not limited to: monoclonal antibodies, polyclonal antibodies, proteins, such as but not limited to rnase H, nucleic acids, including but not limited to aptamers, or sequence-specific nucleic acids. In one aspect, an antibody that binds to the formed double-stranded nucleic acid hybrid is used as a binding agent, and the corresponding antibody is also referred to as an anti-hybrid antibody. Thus, antibodies or antibody fragments specific for double-stranded nucleic acid hybrids can be used to capture and detect double-stranded nucleic acid hybrids formed in accordance with the present invention. Subsequently, we will describe suitable and preferred embodiments with reference to antibodies. However, the description applies equally to antibody fragments capable of binding to the hybrid, such as Fab fragments, or other suitable anti-hybrid binding agents that may be used as the first binding agent.

The antibodies are specific for double-stranded hybrids such as, but not limited to, RNA/DNA hybrids, DNA/DNA hybrids, RNA/RNA hybrids, and mimetics thereof, wherein mimetics refer to molecules having properties similar to those of RNA/DNA, DNA/DNA, or RNA/RNA hybrids. The anti-double stranded nucleic acid hybrid antibody used, i.e., the anti-hybrid antibody, depends on the type of double stranded nucleic acid hybrid formed. In one aspect, the anti-hybrid antibody is immunospecific for RNA/DNA hybrids. It will be appreciated by those skilled in the art that polyclonal or monoclonal hybrid antibodies can be utilized and/or immobilized on a carrier in the present invention, as described below. In one aspect, the monoclonal antibody supports a high stringency incubation temperature during the capture step. The first and further binding agents (preferably antibodies) may be the same, or may be different from each other, in terms of capture and detection. In one aspect, the first and further binding agents (which may be labelled, see below) (preferably both monoclonal antibodies) are the same, specific for RNA-DNA hybrids, both in terms of capture and detection. As mentioned above, double-stranded hybrid-specific antibody immunological fragments or derivatives are also suitable as binding agents, such fragments or derivatives comprising the binding region of an antibody.

In one aspect of the invention, monoclonal anti-RNA/DNA hybrid antibodies derived from hybridoma cell lines are utilized. Such hybridoma cell lines are described in U.S. patent No. 4,865,980, U.S. patent No. 4,732,847, and U.S. patent No. 4,743,535. Monoclonal antibodies specific for the hybrid can also be prepared using techniques standard in the art. Monoclonal antibodies specific for the hybrid can be used to capture and detect target nucleic acids simultaneously. Other binding agents suitable for specifically binding the formed hybrid may also be used as the first binding agent in order to capture the hybrid.

In one aspect, a first anti-hybrid binding agent, e.g., an anti-hybrid antibody, is immobilized to the support using techniques standard in the art. Examples of suitable immobilization techniques include covalent bonds or adsorption, e.g., protein-protein interactions, protein-G beads, biotin-streptavidin interactions, EDAC to attach carboxyl or tosyl groups, etc., using, e.g., sequence specific nucleic acids in affinity columns or coating schemes directly to the solid support.

Supports include, but are not limited to: reaction vessel comprising a microtiter plate, wherein one or more wells are functionalized with molecules capable of binding hybrids, preferably microtiter plates functionalized with anti-hybrid antibodies, particles, magnetic particles, columns, plates, filter papers and dipsticks. . Any support may be utilized as long as it allows removal, e.g., extraction of the liquid phase. Magnetic particles are useful if a magnetic field is applied to immobilize the hybrid-bound particles or magnetic particles, since they can remain in solution and the liquid phase can be extracted or decanted and removed using the system described above. Particles that are small and have a high surface area, such as particles having a diameter of about 0.5 μm to 10 μm, 0.75 μm to 7.5 μm, 0.75 μm to 5 μm, 0.75 μm to 2.5 μm, and most preferably 1 μm, are preferred. However, when using magnetic particles as a solid support for the first binding agent to bind the hybrids, it is preferred to perform a final magnetic separation step prior to performing step e) to ensure that the magnetic particles do not interfere with the detection.

The support for immobilizing the first binding agent bound to the hybrid produced is preferably a reaction vessel. Preferably, the support is provided by a multi-well device (e.g. a microtiter plate), wherein the wells are at least partially functionalized with a first binding agent. This embodiment is advantageous because it allows convenient removal of particles for binding cells during the assay, which is preferred if the particles are not isolated prior to step d). The resulting hybridosomes are captured by the binding agent and thereby immobilized in the reaction vessel, so that the remaining sample containing particles for binding cells can be conveniently removed, e.g. by aspiration and/or washing.

The hybrids are incubated with the anti-hybrid binding agent attached to the support for a sufficient time to capture double-stranded nucleic acid hybrids by the immobilized anti-hybrid binding agent. Thereby forming a double stranded nucleic acid hybrid/solid support complex further comprising a first binding agent for capturing said hybrids. As noted above, in a preferred aspect, the support is a reaction vessel, preferably a microtiter plate functionalized with one or more anti-hybrid binding agents (e.g., anti-hybrid antibodies). The anti-hybrid antibody may be monoclonal or polyclonal. In one aspect, the antibody is a monoclonal antibody. In one aspect, the antibody is coupled to the support via a 1-ethyl-3- [ 3-dimethylaminopropyl ] carbodiimide hydrochloride (EDAC) linker.

In one aspect, the support is a polystyrene bead. In one aspect, the support or beads coupled to a binding agent (preferably an antibody) are diluted with a bead dilution buffer. The bead dilution buffer helps to minimize denaturation of the proteins on the beads. One example of a bead dilution buffer includes: 6% casein, 100mM Tris-HCl, 300mM NaCl and 0.05% sodium azide.

In one aspect, the support coated with anti-hybrid antibodies is incubated with the sample. The incubation can be carried out at room temperature or at elevated temperature. The incubation time may be from about 5 to about 120 minutes, from about 10 to about 100 minutes, or from about 20 to about 80 minutes, or from about 30 minutes to about 60 minutes, and any number within the range sufficient for capture. The same incubation time is suitable if the first binding agent used to bind the formed hybrid is not bound to the solid support. The sample may be shaken during the incubation. One skilled in the art will appreciate that incubation time, temperature, and/or shaking conditions can be varied as desired to achieve other capture kinetics.

After target nucleic acid/probe hybrid binding and capture thereby, the captured hybrid can be separated from the remaining sample. Separation is particularly easy if the first binding agent is immobilized to a solid support. In this case, the unbound sample may, for example, simply be aspirated, as also described in the examples. According to one embodiment, one or more washing steps are performed to wash out uncaptured nucleic acids and remaining sample. As mentioned above, if the particles for binding cells are still present during the generation and capture of the hybrids, they will be partially removed during the separation step and/or subsequent washing steps, if this is preferably done. As mentioned above, the particles are preferably magnetic particles, preferably carrying PEI as anion exchange moiety on their surface. Advantageously, there is no need to specifically remove particles, for example by means of a magnet in the case of magnetic particles, since they are automatically removed during the separation of the remaining sample and/or the subsequent washing step, which is preferably done so. This again saves processing steps.

According to one embodiment, another binding agent is used in step d). The other binding agent may comprise a detectable label. The other binding agent is used to detect the presence of a double-stranded nucleic acid hybrid. If the first binding agent is immobilized to the solid support, another binding agent may be directly or indirectly attached to the complex formed upon binding of the first binding agent, thereby capturing the formed hybrid, thereby providing a double-stranded nucleic acid hybrid/first binding agent/labeled binding agent complex or double-stranded nucleic acid hybrid/solid support/labeled binding agent complex. In one aspect, the other binding agent comprises a label that must react with the substrate to provide a detectable signal. The other binder may be dissolved in a suitable buffer. In one aspect, the buffer comprises 100mM Tris HCl, pH 7.4, 0.5M NaCl, 0.1mM ZnCl₂、1.0mM MgCl₂0.25% tween 20, 0.2mg/ml rnase a, 4% hydroxypropyl- β -cyclodextrin (cyclodextrin), 30% bead dilution buffer as described previously, 0.05% goat IgG, 0.05% sodium azide preferably the other binding agent is an antibody or fragment thereof, preferably a monoclonal antibody.

According to one embodiment, the further binding agent comprises a detectable label and binds to a hybrid with double stranded nucleic acid. Alternatively, another binding agent comprising a detectable label is bound to the first binding agent. Alternatively, a second binding agent that is not directly labeled may be used to detect the formation of a double-stranded nucleic acid hybrid. In this embodiment, a second binding agent capable of binding another binding agent comprising a detectable label may be used to bind the double-stranded nucleic acid hybrid or the first binding agent. For example, the second binding agent may be a mouse immunoglobulin, such as a goat anti-mouse antibody, detected by a labeled third antibody. Corresponding binding protocol strategies suitable for providing complexes with detectable labels are well known in the art and need not be further described herein.

In one aspect, the binding reaction between the labeled binding agent and the complex containing the capture hybrid occurs at room temperature. In one aspect, the conjugation reaction is carried out at room temperature for about 15 minutes to 120 minutes, 20 minutes to 100 minutes, 25 minutes to 80 minutes, 30 minutes to 60 minutes, or 30 minutes to 45 minutes. The binding reaction may occur at room temperature or at elevated temperature.

One skilled in the art will appreciate that any detectable label may be utilized, such as, but not limited to, an enzyme, a radioactive molecule, a fluorescent molecule, or a metal particle, such as a gold particle. In certain aspects, the detectable label is alkaline phosphatase. Methods of conjugating labels to antibodies are known. For example, an antibody can be reduced with Dithiothreitol (DTT) to yield a monovalent antibody fragment. The reduced antibody can then be directly coupled to maleated alkaline phosphatase by the methods of Ishikawa et al (J.Immunoasay 4:209-237(1983)) and Means et al (chem.1:2-12(1990)), each of which is incorporated by reference in its entirety, and the resulting conjugate can be purified by HPLC. The conjugate may also be purified using any type of size exclusion chromatography. One advantage of purification is that conjugates containing one protein and one antibody can be separated from those conjugates having other protein-antibody ratios.

Washing machine

After binding to another binding agent comprising a detectable label, the sample may be washed with a wash buffer. The wash buffer may comprise one or more detergents, or may be detergent-free. If the wash buffer contains a detergent, the detergent is preferably an ionic or non-ionic detergent. An example of a non-ionic detergent is Triton-X. The detergent is present in the wash buffer at a concentration of about 0.05% to about 1.5%, or about 0.075% to about 1.0%, or about 0.1% to about 0.75%, or about 0.5%, or any number within the stated range. An example of a suitable wash buffer contains 40mM Tris, pH8.2, 100mM NaCl, 0.5% Triton-X100 and 0.05% sodium azide.

The sample may be washed 1-10 times, or 3-7 times, or 4-6 times, or 5 times, or any number within the stated range, with the wash buffer. The sample may also be washed with a single wash buffer, or multiple wash buffers. The same wash buffer or a different wash buffer may be used for each wash. For example, a wash buffer containing detergent may be used for one wash, while a wash buffer without detergent may be used for another wash. In one aspect, one of the wash buffers does not contain Triton.

An advantage of performing the one or more washing steps is that the remaining traces of magnetic particles used to bind the cells and present during the capture of the hybrids can be effectively washed away, and can therefore be removed before performing the detection step e). These particles are particularly easy to wash out if they have a size of 7.5 μm or less, preferably 5 μm or less, more preferably 2.5 μm or less. Therefore, according to a preferred embodiment, no magnetic separation step is performed before step d) in order to remove the magnetic particles used for collecting the cells.

Step e) -detection

In step e), the label present on the other binding agent is detected, thereby indicating the presence or absence of the target nucleic acid molecule. Methods for detecting various markers are known in the art. For example, the colorimetric, radioactive, surface plasmon resonance or chemiluminescent methods described by Coultee et al, J.Clin.Microbiol.27:1002-1007(1989), the contents of which are incorporated herein by reference in their entirety.

For example, a conjugate that binds alkaline phosphatase can be detected by chemiluminescence using a detection reagent such as LUMI-PHOS 530 reagent (Lumigen, detroit, Mich) or DR2 instrument (Applied Biosystems, Foster City, Calif.), using a detector such as a FVUMINA photometer (Source Scientific Systems, Inc. -SSS, Calif.), OPTOCOMP I photometer (MGM instruments, Hamden, Connecticut), etc., such as a Veritas microplate photometer (Turner Biosystems). Multiple detection techniques may also be used sequentially or in parallel. For example, the conjugate may be detected by chemiluminescence and/or fluorescence. In another aspect, the conjugate can be detected by chemiluminescence.

As described herein, detection of a label indicates the presence of one or more target nucleic acid molecules in the sample that are complementary to one or more probes. After washing (see above), the sample is suspended in a detection buffer, e.g. comprising a label substrate on a labeled binding agent.

One of the reasons why the presence of HPV or other target nucleic acid molecules can be determined in a short time is that methods based on hybrid capture do not require amplification of the target nucleic acid molecule prior to detection. Without amplifying the target, signal amplification can be used to accurately detect the presence of HPV or other target nucleic acid molecules. In one aspect, the method of the present invention may comprise a signal amplification step. In one aspect, the method of the invention does not comprise a target amplification step, in particular a PCR amplification step in step d), or preferably, a target amplification step is not included at all. In another aspect, the methods of the invention can include a signal amplification step without an amplification step of the target nucleic acid.

The present invention also provides methods and assays for detecting cancer or determining the risk of developing cancer (e.g., cervical cancer) by detecting the presence of a target nucleic acid molecule (e.g., HPV) in a sample using the methods described above.

One skilled in the art will appreciate that detection can be performed in a variety of platforms, including, but not limited to, test tubes, dipsticks, microarrays, microplates, 384-well plates, other microtiter plates, and microfluidic systems.

Target nucleic acid

The target nucleic acid can be of any type and can be selected from: cellular nucleic acids, preferably genomic DNA or cellular RNA, nucleic acids derived from tumors, nucleic acids derived from pathogens, e.g. pathogen nucleic acids, in particular viral nucleic acids. In exemplary embodiments, the target nucleic acid is derived from a pathogen, such as a microorganism or a virus. In a further embodiment, the nucleic acid is derived from a virus. In a further aspect, the viral nucleic acid is a virus-derived DNA molecule associated with the cell in an intact virus or viral capsid; maintained in the cell episome; or integrated into a cellular DNA molecule, such as a chromosome of a cell. In further embodiments, the viral nucleic acid is mRNA encoded by a viral gene or a cDNA molecule derived from such mRNA. If the target nucleic acid is cDNA, a reverse transcription step is employed. In a further embodiment, the target nucleic acid is derived from a human papilloma virus. In a further embodiment, the automated method is a method of analyzing or screening for the presence of high risk human papillomavirus in a clinical sample.

In one embodiment, the target nucleic acid molecule is at least 70%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identical to a nucleic acid molecule associated with or comprised by any of the following samples: cervical samples (e.g., samples taken from cervical swabs) or cervical cell samples, adenoid cells, anal epithelial cells, blood, saliva, cerebrospinal fluid, pleural fluid, milk, lymph fluid, sputum, urine and semen, other cell samples containing viruses, bacteria, mycobacteria or plasmodium, such as Cytomegalovirus (CMV), HPV, herpes virus, HIV, H1N1, Chlamydia, gonococci, neisseria (Neisseriagonorrhoeae, GC), Chlamydia Trachomatis (CT), trichomonas vaginalis (trichomonas vaginalis), Staphylococcus aureus (Staphylococcus aureus), mycobacterium tuberculosis, SARS-associated coronavirus or influenza virus or cell samples suspected to contain the corresponding pathogen.

In one embodiment, the target nucleic acid molecule is derived from Human Papillomavirus (HPV), including genetic variants of HPV. Variants include polymorphisms, mutants, derivatives, modified, altered, etc., of the target nucleic acid. In one aspect, the target nucleic acid is an HPV nucleic acid. In another aspect, the HPV nucleic acid is HPV DNA of a high-risk HPV type. In another aspect, the HPV nucleic acid is an HPV RNA of a high-risk HPV type. In another aspect, the target nucleic acid is any one of the following high risk HPV types: 16. 18, 26, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68, 82, or any of the following low risk HPV types: 6. 11, 40, 43,53, 61, 67, 69, 70, 71, 72, 81 and 83. In one aspect, the target nucleic acid molecule is at least 70%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identical to a nucleic acid molecule associated with any of HPV, a genetic variant of HPV, HPV DNA of high risk HPV type, or HPV RNA of high risk HPV type. In another aspect, the target nucleic acid is at least 70%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% identical to a nucleic acid molecule associated with any one of the following high risk HPV types, said high risk HPV types being 16, 18, 26, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68, and 82, or a nucleic acid molecule associated with any one of the following low risk HPV types, said low risk HPV types being 6, 11, 40, 43,53, 61, 67, 69, 70, 71, 72, 81, and 83.

The target nucleic acid molecule can be DNA or RNA. In one aspect, the target nucleic acid to be detected is DNA (e.g., HPV genomic DNA or cDNA) or RNA (e.g., mRNA, ribosomal RNA, nuclear RNA, transfer RNA, viral RNA, heterologous nuclear RNA, small non-coding RNA, siRNA, miRNA), wherein the one or more polynucleotide probes are each a polyribonucleotide or polydeoxyribonucleotide, or mixtures thereof. The probe may also comprise modified nucleotides. The polynucleotide probe is preferably RNA when the target nucleic acid molecule is DNA, and DNA when the target nucleic acid molecule is RNA. However, DNA probes can be used for DNA target nucleic acid molecules and RNA probes can be used for RNA target nucleic acid molecules. In a preferred aspect, the double-stranded nucleic acid hybrid is a DNA-RNA hybrid formed by hybridization of the target DNA and the probe RNA, and can be detected using immunospecific antibodies for the RNA-DNA hybrid.

In a preferred embodiment, the target nucleic acid is derived from a pathogen, such as a microorganism or a virus. In further embodiments, the target nucleic acid is derived from a virus. In a further aspect, the viral nucleic acid is a viral-derived DNA molecule, can be present in an intact virus or viral capsid, can be included in episomes in the cell or can be integrated into a cellular DNA molecule, such as a chromosome of the cell. In further embodiments, the viral nucleic acid is mRNA encoded by a viral gene or a cDNA molecule derived from such mRNA. In one embodiment, the target nucleic acid is derived from a human papilloma virus. In one embodiment, the automated method is a method of analyzing or screening for the presence of high risk human papillomavirus in a clinical sample.

The process of the invention is particularly advantageous in that it can be fully automated. The use of a surface comprising anion exchange moieties, particularly in the form of magnetic beads comprising anion exchange moieties (e.g., PEI), enables cell separation, lysis and nucleic acid analysis without the need for a centrifugation step, thereby enabling high throughput sample processing and analysis.

In one embodiment, the detecting step e) comprises using an analyzer comprising: (1) a heating element; and (2) a device that detects a detectable signal, such as a fluorometer or luminometer.

In a further embodiment, an automated method for detecting a target nucleic acid is provided, the method comprising immobilizing the mammalian cell, lysing the cell, as described above, thereby releasing the nucleic acid in the lysate; and detecting nucleic acids by a method of producing DNA: RNA hybrids.

In a further embodiment, an automated method of analyzing or screening a clinical sample for a disease state is provided, the method comprising: (a) immobilizing cells contained in the sample on a surface comprising an anion exchange moiety, as described above; (b) isolating or concentrating the cells, as described above; (c) lysing the cells to produce a lysate; (d) and detecting the presence of the target nucleic acid in the lysate, wherein the presence or absence of the biomolecule in the lysate is indicative of a disease state. Any detection method compatible with automation may be employed. For example, but not limited to, the detection method may comprise hybridizing a nucleic acid probe to the nucleic acid in the lysate. For example, but not limited to, hybridization produces DNA RNA hybrids. In a further embodiment, the DNA RNA hybrid is detected by binding a DNA RNA hybrid specific antibody to the DNA RNA hybrid between the nucleic acid probe and the nucleic acid of the lysate.

In a further embodiment, an automated method of analyzing or screening a clinical sample for a disease state is provided, the method comprising performing steps a) to e) above, wherein the presence or absence of the target nucleic acid in the cell lysate is indicative of the disease state. Any detection method compatible with automation may be employed. For example, but not limited to, the nucleic acid probe hybridizes to the target nucleic acid of the lysate. For example, but not limited to, hybridization produces DNA RNA hybrids. In a further embodiment, the DNA RNA hybrid is captured by binding a DNA RNA hybrid specific antibody to the DNA RNA hybrid between the nucleic acid probe and the target nucleic acid of the lysate. The captured hybrid is then detected.

Particularly preferred embodiments

While suitable and preferred embodiments of the invention have been described above, it will also be understood by those skilled in the art that the various steps a) through e) and the components and reagents used, and that the various steps and components and reagents utilized in the methods may be combined with one another. The subject matter of the respective combinations of the features also belongs to the invention. The following text will emphasize non-limiting, particularly preferred embodiments of the invention.

According to a first particularly preferred embodiment, the method for determining the presence or absence of a target nucleic acid in a cell sample comprises the following steps:

a) contacting the surface comprising the anion exchange moiety with a sample of cells under conditions suitable to induce binding between the cells and the surface, wherein cell binding occurs at a pH at which the anion binding group of the anion binding moiety is positively charged, wherein preferably cell binding occurs at a pH selected from the range: 3-8.5, 3.5-8, 3.75-7.75, 4-7.5, 4.25-7.25 or 4.5-7;

b) separating the cell-bound surface from the remaining sample to collect cells;

c) releasing nucleic acids from the cells and denaturing the released nucleic acids;

d) generating a hybrid between a target nucleic acid and a probe specific for the target nucleic acid, wherein step d) comprises:

-contacting the sample containing released and denatured nucleic acids with one or more target nucleic acid specific probes, preferably forming RNA/DNA hybrids, under conditions that allow hybridization of the probes to single-stranded target nucleic acid molecules to form double-stranded nucleic acid hybrids;

-capturing the double-stranded nucleic acid hybrid using a binding agent that binds to the double-stranded nucleic acid hybrid;

-optionally separating the captured double stranded nucleic acid hybrid from unbound nucleic acids;

-optionally washing the captured double stranded nucleic acid hybrids;

e) detecting the presence or absence of the double-stranded nucleic acid hybrid, thereby indicating the presence or absence of the target nucleic acid.

Suitable and preferred embodiments of the anion exchange surface, the cell sample and steps a) to e) are described in detail above, with reference to the above disclosure, which is also applicable here and can be combined with the first particularly preferred embodiment. Preferably, the anion exchange surface is provided by magnetic particles, in particular PEI functionalized magnetic particles, as detailed above, for example. Furthermore, the surface may also comprise additional functional groups, preferably acidic groups, such as carboxyl groups. The carboxyl groups may be used for PEI functionalization as detailed above. Reference is made to the above. Furthermore, as mentioned above, if magnetic particles are used, the magnetic particles are preferably not removed prior to step d) to save processing steps. Thus, preferably, the anion exchange surface is resistant to degradation under the conditions used in step d). Furthermore, as mentioned above, preferred cell samples comprise cells contained in a liquid-based cytology medium, in particular cervical cells. Reference is made to the above.

According to a second particularly preferred embodiment, the method for determining the presence or absence of a target nucleic acid in a cell sample comprises the following steps:

a) contacting a surface comprising an anion exchange moiety with a cell sample under conditions suitable to induce binding between the cell and the surface, wherein the anion exchange moiety comprises at least one primary amine, at least one secondary amine, and/or at least one tertiary amine group, wherein cell binding occurs at a pH value selected from the following pH ranges: 3.5-8, 3.75-7.75, 4-7.5, 4.25-7.25, or 4.5-7, wherein the amino groups of the anion exchange moiety are positively charged at the pH, wherein the binding conditions are not adjusted;

b) separating the cell-bound surface from the remaining sample to collect cells;

c) contacting the collected anion exchange surface-bound cells with a liquid composition that promotes the release of nucleic acids from the cells, wherein the liquid composition has one or more, preferably at least two, at least three, more preferably all of the following characteristics i to v:

i. it comprises a chaotropic agent;

it has an alkaline pH;

it has a pH selected from: 12 or higher, 12.5 or higher, 13 or higher, or 13.25 or higher;

it comprises one or more additives, preferably

aa) a chelating agent;

bb) a buffer; and/or

cc) preservative

v. the liquid composition is obtained by mixing two or more compositions, wherein one of the compositions comprises a chaotropic agent, one of the compositions is an alkaline solution comprising an alkaline agent (preferably NaOH or KOH), preferably in a concentration of 1.0N to 2.0N;

and releasing the nucleic acid from the cells and denaturing the released nucleic acid, wherein releasing and/or denaturing the nucleic acid comprises heating, and wherein preferably a sample mixture comprising the liquid composition, the cells and/or lysed cells and optionally the anion exchange surface, or an aliquot of said mixture, is transferred to a new container, preferably to the wells of a multi-well device, prior to heating;

d) generating a hybrid between the target nucleic acid and a probe specific for the target nucleic acid, wherein step d) comprises:

-contacting the sample containing released and denatured nucleic acids with one or more target nucleic acid specific probes, preferably forming RNA/DNA hybrids, under conditions that allow hybridization of the probes to single-stranded target nucleic acid molecules to form double-stranded nucleic acid hybrids;

-capturing the double-stranded nucleic acid hybrid using a binding agent that binds to the double-stranded nucleic acid hybrid;

-optionally separating the captured double stranded nucleic acid hybrid from unbound nucleic acids;

-optionally washing the captured double stranded nucleic acid hybrids;

e) detecting the presence or absence of a double-stranded nucleic acid hybrid, thereby indicating the presence or absence of the target nucleic acid.

Suitable and preferred embodiments of the anion exchange surface, the cell sample, the liquid composition and steps a) to e) are described in detail above, with reference to the above disclosure, which is also applicable here and can be combined with the second particularly preferred embodiment. Preferably, the anion exchange surface is provided by magnetic particles, in particular PEI functionalized magnetic particles, as detailed above, for example. Furthermore, the surface may also comprise additional functional groups, preferably acidic groups, such as carboxyl groups. The carboxyl groups may also be functionalized with PEI as detailed above. Reference is made to the above. Furthermore, as mentioned above, if magnetic particles are used, the magnetic particles are preferably not removed prior to step d) to save processing steps. Thus, preferably, the anion exchange surface is resistant to degradation under the conditions used in step d). Furthermore, as mentioned above, the cell sample preferably comprises cells, in particular cervical cells, contained in a liquid-based cytology medium. Reference is made to the above.

According to a third particularly preferred embodiment, the method for determining the presence or absence of a target nucleic acid in a cell sample comprises the following steps:

a) contacting a surface comprising an anion exchange moiety with a cell sample under conditions suitable to induce binding between the cells and the surface, wherein the surface is provided by magnetic particles, wherein cell binding occurs at a pH value selected from the following pH ranges: 3.5-8, 3.75-7.75, 4-7.5, 4.25-7.25 or 4.5-7, wherein the anion exchange groups of the anion exchange moiety are positively charged at said pH, wherein preferably no adjustment of the binding conditions is performed;

b) separating the magnetic particles with the bound cells from the remaining sample to collect the cells;

c) contacting the collected magnetic particle-bound cells with a liquid composition that promotes the release of nucleic acids from the cells, wherein the liquid composition has one or more, preferably at least two, at least three, more preferably all of the following characteristics i to v:

i. it comprises a chaotropic agent;

it has an alkaline pH;

it has a pH selected from: 12 or higher, 12.5 or higher, 13 or higher, or 13.25 or higher;

it comprises one or more additives, preferably

aa) a chelating agent;

bb) a buffer; and/or

cc) preservative

And/or

v. the liquid composition is obtained by mixing two or more compositions, wherein one of the compositions comprises a chaotropic agent, one of the compositions is an alkaline solution comprising an alkaline agent (preferably NaOH or KOH), preferably in a concentration of 1.0N to 2.0N;

and releasing the nucleic acid from the cell and denaturing the released nucleic acid; wherein releasing and/or denaturing the nucleic acid comprises heating, and wherein preferably the sample mixture comprising the liquid composition, the cells and/or lysed cells and the magnetic particles, or an aliquot of said mixture, is transferred to a new container, preferably to the wells of a multi-well device, prior to heating;

d) generating a hybrid between the target nucleic acid and a probe specific for the target nucleic acid, wherein the magnetic particles are not magnetically separated prior to step d), wherein step d) comprises:

-contacting the sample containing the released and denatured nucleic acids and magnetic particles for binding to cells with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single stranded target nucleic acid molecules to form double stranded nucleic acid hybrids;

-capturing the double-stranded nucleic acid hybrid with a first binding agent that binds to the double-stranded nucleic acid hybrid, thereby forming a double-stranded nucleic acid hybrid/first binding agent complex;

-separating the double stranded nucleic acid hybrid/first binding agent complex from unbound nucleic acids, thereby removing at least a portion of the magnetic particles;

-binding the complex with another binding agent labelled with a detectable label to form a double stranded nucleic acid hybrid/first binding agent/labelled binding agent complex;

-washing the double stranded nucleic acid hybrid/first binding agent/labelled binding agent complex, wherein said washing removes remaining magnetic particles, if still present;

e) detecting the presence or absence of a double-stranded nucleic acid hybrid, thereby indicating the presence or absence of the target nucleic acid.

Suitable and preferred embodiments of the magnetic particles, the cell sample, the liquid composition and steps a) to e) are described in detail above, with reference to the above disclosure, which is also applicable here and can be combined with the third particularly preferred embodiment. The anion exchange surface provided by the magnetic particles is preferably resistant to degradation under the conditions used in step d). For example, as detailed above, magnetic particles functionalized with PEI are preferred, more preferably the magnetic particles have an average size of 7.5 μm or less, more preferably 5 μm or less. The magnetic particles may also carry acidic functional groups, such as carboxyl groups, on their surface, which may also be used for PEI functionalization of the surface, as described above. Reference is made to the above for further details of the magnetic particles, the concentration of the magnetic particles used and/or other reagents or components used in the method of the invention. Furthermore, as mentioned above, the cell sample preferably comprises cells, in particular cervical cells, contained in a liquid-based cytology medium. Reference is made to the above.

According to a fourth particularly preferred embodiment, steps d) and e) of the method of the third particularly preferred embodiment comprise:

step d):

-contacting the sample containing the released and denatured nucleic acids and magnetic particles for binding to cells with one or more target nucleic acid specific probes under conditions that allow hybridization of the probes to single stranded target nucleic acid molecules to form double stranded nucleic acid hybrids;

-capturing the double-stranded nucleic acid hybrids on a solid support coated with a first binding agent that binds the double-stranded nucleic acid hybrids, thereby forming double-stranded nucleic acid hybrid/solid support complexes;

-separating the double stranded nucleic acid hybrid/solid support complex from unbound nucleic acids, thereby removing at least a portion of the magnetic particles;

-binding the complex to another binding agent labelled with a detectable label to form a double stranded nucleic acid hybrid/solid support/labelled binding agent complex;

-washing the double-stranded nucleic acid hybrid/solid support/labeled binding agent complex with a washing buffer, wherein said washing removes remaining magnetic particles, if still present;

step e):

-detecting the presence or absence of the label of the further binding agent, thereby indicating the presence or absence of the target nucleic acid.

According to a fifth particularly preferred embodiment, the method of the third or fourth particularly preferred embodiment is characterized in that, after contacting the cell sample with the magnetic particles in step a), said magnetic particles are contained in the resulting mixture in a concentration selected from the group consisting of: 50-2000. mu.g/ml, 75-1750. mu.g/ml, 100-1500. mu.g/ml, 125-1250. mu.g/ml and 150-1100. mu.g/ml. Furthermore, as mentioned above, the collected magnetic particle-bound cells are preferably contacted with a volume of the liquid composition selected from the group consisting of: 50 μ l to 200 μ l, 60 μ l to 175 μ l, 70 μ l to 150 μ l, 80 μ l to 125 μ l, and 85 μ l to 100 μ l.

As mentioned above, the method of the present invention and thus of the first, second, third, fourth or fifth particularly preferred embodiment is preferably an automated method, wherein the sample treatment is performed with a robotic system. This is particularly feasible if the anion exchange surface is provided by magnetic particles. The methods can be used to analyze a sample, e.g., a clinical sample, for a disease state and/or the presence or absence of pathogen nucleic acid. In particular, as shown in the examples, the methods can be used in the HPV diagnostic field to determine the presence or absence of HPV nucleic acids, particularly high-risk HPV nucleic acids, in cervical samples collected in liquid-based cytology media.

Reagent kit

Furthermore, the invention provides kits suitable for carrying out the methods of the invention.

According to an embodiment, there is provided a kit comprising

a) Magnetic particles, wherein the surface of the magnetic particles comprises an anion exchange moiety;

b) a denaturant which is an alkaline solution containing an alkali (preferably NaOH or KOH), preferably in a concentration range of 1.0N to 2.0N; and

c) a composition comprising a chaotropic agent and optionally one or more additives selected from the group consisting of chelating agents, buffers and preservatives.

According to a preferred embodiment of the kit, the kit comprises a kit comprising a plurality of wells, wherein

a) The first tank of the kit contains magnetic particles, wherein the surfaces of the magnetic particles comprise an anion exchange moiety;

b) the second tank of the kit contains a denaturant, which is an alkaline solution containing a base (preferably NaOH or KOH), preferably at a concentration of 1.0N-2.0N; and

c) the third tank of the kit comprises a composition comprising a chaotropic agent and optionally one or more additives selected from the group consisting of chelating agents, buffers and preservatives.

The cartridge may be sealed (e.g., with a cap) to avoid contamination of the contained reagents. The respective cartridge may be used in conjunction with an automated system (e.g. a robotic system) capable of handling magnetic particles. Suitable and preferred examples of the respective automated systems are described above. Each cartridge is inserted into an automated system to provide the reagents required to process a sample using the automated system according to the method of the first aspect of the invention. The invention therefore also relates to an automated system capable of handling magnetic particles, said system comprising a cartridge as described above. A cartridge may be inserted into the robotic system. Details of the magnetic particles, denaturants, chaotropic agent-containing compositions, automation system and method of the first aspect are detailed above. Reference is made to the above. Preferably, in addition to the kit, the kit is equipped with an elution plate comprising a plurality of wells, wherein the wells are adapted to receive the collected cells. After sample processing by an automated system using the above reagent kit, cells collected from an individual sample by binding to magnetic particles are transferred to the wells of an elution plate together with the magnetic particles. The corresponding elution plate containing the collected cells may then be subjected to the hybrid capture assay described above.

Details of the magnetic particles, suitable and preferred anion exchange moieties, particle size, magnets, etc. have been described above in connection with the methods. Reference is made to the above, and they are also applicable here.

As mentioned above, the magnetic particles are preferably functionalized with polyethyleneimine as the anion exchange moiety. The advantages are as explained above. As mentioned above, the magnetic particles are preferably provided in the form of a particle suspension. Suitable and preferred embodiments of the particle suspension are described above, reference being made to the corresponding statements, which also apply here. As described above, the pH of the particle suspension is preferably 7.5 or less, 7 or less, 6.5 or less. Furthermore, as mentioned above, the particles are preferably contained in a suspension at a concentration selected from: 5mg/ml to 50mg/ml, 10mg/ml to 25mg/ml, 10mg/ml to 20mg/ml and 12.5mg/ml to 17.5 mg/ml.

The kit comprises a denaturant which is an alkaline solution containing a base, preferably NaOH or KOH, preferably in a concentration range of 1.0N-2.0N. However, higher concentrations of the base solution may also be used. Furthermore, the kit comprises a composition comprising a chaotropic agent and optionally one or more additives selected from the group consisting of chelating agents, buffers and preservatives. By mixing the denaturing agent and the composition comprising the chaotropic agent, a liquid composition is provided which facilitates the release and/or denaturation of nucleic acids. Details as mentioned above, reference is made to the corresponding matters, which are also applicable here. The respective mixing step is preferably performed by means of an automated system as described above.

Optionally, the kit may also include reagents for performing hybrid capture assays, e.g.

-at least one probe suitable for hybridization with a target nucleic acid; and

-at least one binding agent capable of binding double-stranded nucleic acid hybrids.

Thus, the kit may comprise at least one probe suitable for hybridization to a target nucleic acid. Information on suitable and preferred probes and target nucleic acids has been described above in connection with the method of the invention, and reference is made to the corresponding matters, which also apply here. The probes are preferably polynucleotide probes, in particular RNA probes, which, when bound to a single-stranded target DNA, form a DNA/RNA hybrid. The at least one probe is preferably suitable for hybridization to an HPV target nucleic acid. Details are described above in connection with the method of the invention; reference is made to the above, and these are also applicable here. In addition, the kit can comprise at least one binding agent capable of binding double-stranded nucleic acid hybrids. The binding agent is preferably an anti-hybrid antibody or an anti-hybrid binding fragment thereof. Suitable and preferred embodiments of the first binding agent are described above in connection with the method; reference is made to the above. As described above, the at least one binding agent is preferably attached to a solid support, such as the inner surface of a reaction vessel; reference is made to the above. Preferably, the kit comprises at least one further binding agent comprising a detectable label. Details for the further binding agent and suitable label are described above in connection with the method; reference is made to the above. The other binding agent is preferably conjugated to alkaline phosphatase as a detectable label. In addition, the kit may comprise one or more detection reagents. Details are described above in connection with the method, to which reference is made. For example, a chemiluminescent substrate can be included that can be treated with alkaline phosphatase to produce light. In addition, the kit may comprise one or more wash buffers. Suitable embodiments are described above in connection with step d) of the method. Reference is made to the corresponding contents, which are also applicable here.

According to one aspect, there is provided a kit comprising:

a) magnetic particles, wherein the surface of the magnetic particles comprises an anion exchange moiety;

b) at least one probe suitable for hybridization to a target nucleic acid; and

c) at least one binder capable of binding double stranded nucleic acid hybrids.

The kit may also be provided by combining two separate kits, e.g. two of the above-mentioned kits. The components of the kit are as described above.

The term "solution", e.g. a lysis solution, as used herein especially refers to a liquid composition, preferably an aqueous composition. It may be a homogeneous mixture of only one phase, but solutions comprising solid components (e.g. precipitates) used according to the invention are also within the scope of the invention.

According to one embodiment, the subject matter described herein refers to a subject matter consisting of corresponding steps or ingredients, including certain steps in the case of a method, and certain ingredients in the case of a composition, solution, and/or buffer.

The present invention is not limited to the exemplary methods and materials disclosed herein, but any methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention. Numerical ranges include the numbers defining the range. The headings provided herein are not limitations of the various aspects or embodiments of the invention which can be had by reference to the specification as a whole. The preferred embodiments described herein are preferably selected and combined, and the particular subject matter resulting from the respective combinations of the preferred embodiments also belongs to the present invention.

Priority of the present application claims priority from prior application US 61/695,042 filed on 8/30/2012 and EP12182339.7 filed on 8/30/2012, the entire contents of these prior applications being incorporated herein by reference.

The process of the invention will now be described by way of non-limiting examples.

Examples