Microcapsule compositions and methods
阅读说明：本技术 微胶囊组合物及方法 (Microcapsule compositions and methods ) 是由 本杰明·辛德森 瑟奇·萨克森诺夫 于 2013-08-13 设计创作，主要内容包括：本公开内容提供了微孔胶囊阵列装置。该微孔胶囊阵列装置通常能够进行一个或多个样品制备操作。这样的样品制备操作可用作一个或多个分析操作的前序。例如,本公开内容的装置可在准备多种分析操作中实现样品的物理分割以及样品与独特分子标识符在单个单元内的离散混合。该装置可用于多种应用,最值得注意的是基于核酸的测序、基因表达的检测和量化以及单细胞分析。(The present disclosure provides a microwell capsule array device. The microwell capsule array device is generally capable of performing one or more sample preparation operations. Such sample preparation operations may be used as a prelude to one or more analytical operations. For example, the device of the present disclosure may enable physical partitioning of a sample and discrete mixing of the sample with a unique molecular identifier within a single unit in preparation for a variety of analytical operations. The device can be used in a variety of applications, most notably nucleic acid-based sequencing, detection and quantification of gene expression, and single cell analysis.)
1. A method for sample preparation, comprising:
a) providing a partition comprising gel beads and a nucleic acid analyte, wherein the gel beads comprise at least 1,000,000 oligonucleotide molecules coupled thereto, wherein the at least 1,000,000 oligonucleotide molecules comprise a common barcode sequence;
b) applying a stimulus to release the at least 1,000,000 oligonucleotide molecules from the gel particles, wherein oligonucleotide molecules of the at least 1,000,000 oligonucleotide molecules are attached to the target analyte in the partition; and is
c) Subjecting the oligonucleotide molecules attached to the nucleic acid analyte to a nucleic acid extension reaction to obtain barcoded nucleic acid products.
2. The method of claim 1, wherein the partition is a droplet or a well.
3. The method of claim 1, wherein the at least 1,000,000 oligonucleotide molecules are coupled to the gel bead via an labile moiety.
4. The method of claim 3, wherein the labile moiety is a disulfide bond.
5. The method of claim 1, wherein the stimulus is selected from the group consisting of: biostimulation, chemical stimulation, thermal stimulation, electrical stimulation, magnetic stimulation, and optical stimulation.
6. The method of claim 5, wherein the stimulus is a chemical stimulus, the chemical stimulus being a reducing agent.
7. The method of claim 6, wherein the reducing agent is Dithiothreitol (DTT) or tris (2-carboxyethyl) phosphine (TCEP).
8. The method of claim 1, wherein the oligonucleotide molecules of the at least 1,000,000 oligonucleotide molecules comprise a region that functions as a primer during the nucleic acid extension reaction.
9. The method of claim 8, wherein the region that functions as a primer has a sequence for random priming.
10. The method of claim 8, wherein the primers are configured to amplify the nucleic acid analyte, thereby generating the barcoded nucleic acid product.
11. The method of claim 1, wherein the partition further comprises a polymerase.
12. The method of claim 11, wherein the oligonucleotide molecule comprises uracil and the polymerase does not recognize uracil.
13. The method of claim 1, wherein the nucleic acid analyte is selected from the group consisting of: deoxyribonucleic acid (DNA), ribonucleic acid (RNA), amplicons, synthetic polynucleotides, oligonucleotides, complementary DNA (cdna), double-stranded DNA (dsdna), single-stranded DNA (ssdna), plasmid DNA, cosmid DNA, high Molecular Weight (MW) DNA, chromosomal DNA, genomic DNA, viral DNA, bacterial DNA, mitochondrial DNA (mtdna), messenger RNA (mrna), ribosomal RNA (rrna), transfer RNA (trna), nuclear RNA (nrna), short interfering RNA (sirna), small nuclear RNA (snrna), small nucleolar RNA (snorna), small karha-specific RNA (scarna), micro RNA (microrna), double-stranded RNA (dsrna), ribozymes, riboswitches, and viral RNA.
14. The method of claim 1, wherein the at least 1,000,000 oligonucleotide molecules are coupled to the gel beads via covalent bonds.
15. The method of claim 1, wherein the at least 1,000,000 oligonucleotide molecules are reversibly immobilized to the gel bead.
16. The method of claim 1, wherein the partitions in (a) comprise a plurality of nucleic acid analytes comprising the nucleic acid analyte.
17. The method of claim 16, wherein each of the plurality of nucleic acid analysis species is attached to a single oligonucleotide molecule of the at least 1,000,000 oligonucleotide molecules.
18. The method of claim 16, further comprising fragmenting a nucleic acid sample to obtain the plurality of nucleic acid analytes.
19. The method of claim 1, wherein the oligonucleotide molecules of the at least 1,000,000 oligonucleotide molecules are attached to the nucleic acid analyte by hybridization.
20. The method of claim 1, further comprising, prior to (a), providing a nucleic acid sample and fragmenting the nucleic acid sample to obtain the nucleic acid analyte.
21. The method of claim 1, wherein the gel bead comprises a polymer gel.
22. The method of claim 21, wherein the polymer gel is polyacrylamide.
Background
Detection and quantification of analytes is of crucial importance for molecular biology and medical applications such as diagnostics. Genetic testing is particularly useful for many diagnostic methods. For example, disorders caused by mutations, such as cancer, can be detected or more accurately characterized using DNA sequence information.
Proper sample preparation is often required prior to performing molecular reactions, such as sequencing reactions. The starting sample may be a biological sample, such as a collection of cells, tissues, or nucleic acids. Where the starting material is a cell or tissue, the sample may need to be lysed or otherwise manipulated to allow extraction of molecules such as DNA. Sample preparation may also include fragmenting molecules, isolating molecules, and/or attaching unique identifiers (identifiers) to specific fragments of molecules, among other operations. There is a need in the art for improved methods and apparatus for preparing samples prior to downstream use.
Disclosure of Invention
The present disclosure provides compositions and methods for microcapsule array devices.
One aspect of the present disclosure provides a composition comprising a first microcapsule, wherein: the first microcapsule is degradable when a stimulus is applied to the first microcapsule; and the first microcapsule comprises an oligonucleotide barcode. In some cases, the first microcapsule may comprise a chemical cross-linker. The chemical cross-linker may be, for example, a disulfide bond. In some cases, the composition may comprise a polymer gel, for example, a polyacrylamide gel. The first microcapsule may comprise a bead. In some cases, the bead may be a gel bead.
Further, the stimulus may be selected from the group consisting of biological, chemical, thermal, electrical, magnetic or optical stimuli and combinations thereof. In some cases, the chemical stimulus may be selected from a change in pH, a change in ion concentration, and a reducing agent. The reducing agent may be, for example, Dithiothreitol (DTT) or tris (2-carboxyethyl) phosphine (TCEP).
The second microcapsule may comprise the first microcapsule. Also, the second microcapsule may be a droplet. In some cases, the composition can further comprise a nucleic acid comprising an oligonucleotide barcode, wherein the nucleic acid comprises deoxyuridine triphosphate (dUTP). In some cases, the composition may comprise a polymerase that is unable to accept deoxyuridine triphosphate (dUTP). Moreover, the composition can comprise a target analyte, such as a nucleic acid. The nucleic acid may be selected from the group consisting of DNA, RNA, dNTP, ddNTP, amplicon, synthetic nucleotide, synthetic polynucleotide, oligonucleotide, peptide nucleic acid, cDNA, dsDNA, ssDNA, plasmid DNA, cosmid DNA, high Molecular Weight (MW) DNA, chromosomal DNA, genomic DNA, viral DNA, bacterial DNA, mtDNA (mitochondrial DNA), mRNA, rRNA, tRNA, nRNA, siRNA, snRNA, snoRNA, scaRNA, microRNA, dsRNA, ribozyme, riboswitch (riboswitch), and viral RNA. In some cases, the nucleic acid can be genomic dna (gdna).
In addition, the density of oligonucleotide barcodes may be at least about 1,000,000 oligonucleotide barcodes per first capsule. The oligonucleotide barcodes may be coupled to the microcapsules by chemical cross-linkers (e.g., disulfide bonds).
Another aspect of the present disclosure includes an apparatus comprising a plurality of partitions, wherein: at least one partition of the plurality of partitions comprises microcapsules containing oligonucleotide barcodes; and the microcapsules are degradable when a stimulus is applied to the microcapsules. The partition may be a well or a droplet, for example. In some cases, the microcapsules comprise chemical cross-linkers, such as disulfide bonds. Furthermore, the microcapsules may comprise a polymer gel, such as a polyacrylamide gel. Additionally, the microcapsules may comprise beads. In some cases, the bead may be a gel bead.
The stimulus may be selected from the group consisting of biological, chemical, thermal, electrical, magnetic or optical stimuli and combinations thereof. In some cases, the chemical stimulus may be selected from a change in pH, a change in ion concentration, and a reducing agent. The reducing agent may be, for example, Dithiothreitol (DTT) or tris (2-carboxyethyl) phosphine (TCEP).
In addition, the nucleic acid may comprise an oligonucleotide barcode and the nucleic acid may comprise deoxyuridine triphosphate (dUTP). In some cases, the partition may comprise a polymerase that is unable to accept deoxyuridine triphosphate (dUTP). In addition, the partition can comprise a target analyte, such as a nucleic acid. The nucleic acid may be selected from the group consisting of DNA, RNA, dNTP, ddNTP, amplicon, synthetic nucleotide, synthetic polynucleotide, oligonucleotide, peptide nucleic acid, cDNA, dsDNA, ssDNA, plasmid DNA, cosmid DNA, high Molecular Weight (MW) DNA, chromosomal DNA, genomic DNA, viral DNA, bacterial DNA, mtDNA (mitochondrial DNA), mRNA, rRNA, tRNA, nRNA, siRNA, snRNA, snoRNA, scaRNA, microRNA, dsRNA, ribozyme, riboswitch, and viral RNA. In some cases, the nucleic acid can be genomic dna (gdna). The oligonucleotide barcodes may be coupled to the microcapsules by chemical cross-linkers. In some cases, the chemical cross-linker may be a disulfide bond.
Yet another aspect of the present disclosure provides a method for sample preparation, the method comprising incorporating microcapsules comprising an oligonucleotide barcode and a target analyte into a partition, wherein the microcapsules are degradable when a stimulus is applied to the microcapsules; and applying a stimulus to the microcapsules to release the oligonucleotide barcodes to the target analyte. The partition may be, for example, a well or a droplet. In some cases, the microcapsules may comprise a polymeric gel, such as polyacrylamide. Additionally, the microcapsules may comprise beads. In some cases, the bead may be a gel bead. In addition, the microcapsules may comprise chemical cross-linkers, such as disulfide bonds.
The stimulus may be selected from the group consisting of biological, chemical, thermal, electrical, magnetic or optical stimuli and combinations thereof. In some cases, the chemical stimulus may be selected from a change in pH, a change in ion concentration, and a reducing agent. The reducing agent may be, for example, Dithiothreitol (DTT) or tris (2-carboxyethyl) phosphine (TCEP).
In addition, the nucleic acid may comprise an oligonucleotide barcode and the nucleic acid may comprise deoxyuridine triphosphate (dUTP). In some cases, the partition may comprise a polymerase that is unable to accept deoxyuridine triphosphate (dUTP). Moreover, the method can further comprise attaching an oligonucleotide barcode to the target analyte. The attachment may be accomplished by, for example, a nucleic acid amplification reaction. Furthermore, the analyte may be a nucleic acid. In some cases, the nucleic acid can be selected from the group consisting of DNA, RNA, dNTP, ddNTP, amplicon, synthetic nucleotide, synthetic polynucleotide, oligonucleotide, peptide nucleic acid, cDNA, dsDNA, ssDNA, plasmid DNA, cosmid DNA, high Molecular Weight (MW) DNA, chromosomal DNA, genomic DNA, viral DNA, bacterial DNA, mtDNA (mitochondrial DNA), mRNA, rRNA, tRNA, nRNA, siRNA, snRNA, snoRNA, scaRNA, microRNA, dsRNA, ribozyme, riboswitch, and viral RNA. In some cases, the nucleic acid can be genomic dna (gdna). Furthermore, oligonucleotide barcodes may be coupled to microcapsules by chemical cross-linkers. In some cases, the chemical cross-linker may be a disulfide bond.
Yet another aspect of the disclosure provides a composition comprising degradable gel beads, wherein the gel beads comprise at least about 1,000,000 oligonucleotide barcodes. In some cases, the 1,000,000 oligonucleotide barcodes are identical.
Is incorporated by reference
All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference.
Drawings
The novel features believed characteristic of the device of the disclosure are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the inventive apparatus are utilized, and the accompanying drawings of which:
FIG. 1A is a schematic of a microcapsule or internal reagent droplet.
FIG. 1B is a schematic of a microcapsule containing a plurality of inner reagent droplets.
Fig. 2A is an illustration of a top view of an exemplary microcapsule array.
Fig. 2B is an illustration of an exemplary side view of a microcapsule array.
Figure 3 is a schematic of a multiple microcapsule array configuration on a 96-well plate support.
FIG. 4A is a schematic flow diagram of a reaction sequence in one microwell of a microwell capsule array.
Fig. 4B is similar to fig. 4A, except that there is annotated therein an example of the method that can be performed in each step.
Detailed Description
While various embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed.
I. General overview
The present disclosure provides microwell or other compartmentalized capsule array devices and methods of using such devices. Typically, the device is an assembly of partitions (e.g., microwells, droplets) loaded with microcapsules, typically at a concentration of specific microcapsules/partitions.
The apparatus may be particularly suitable for performing sample preparation operations. In some cases, the device subdivides a sample (e.g., a heterogeneous mixture of nucleic acids, a mixture of cells, etc.) into multiple partitions such that only a portion of the sample is present in each partition. For example, a nucleic acid sample comprising a mixture of nucleic acids can be partitioned such that no more than one strand (or molecule) of nucleic acid is present in each partition. In other examples, the cell sample may be partitioned such that there is no more than one cell in each partition.
After the step of dividing, the subdivided sample may be subjected to any of a number of different operations within the apparatus. The partitions may comprise one or more capsules containing one or more reagents (e.g., enzymes, unique identifiers (e.g., barcodes), antibodies, etc.). In some cases, the device, companion device, or user provides a trigger (trigger) that causes the microcapsules to release one or more reagents into the respective partitions. The release of the reagent may enable the reagent to contact the subdivided sample. For example, if the reagent is a unique identifier, such as a barcode, the sample may be labeled with the unique identifier. The labeled sample can then be used in downstream applications, such as sequencing reactions.
A variety of different reactions and/or operations may be performed within the devices disclosed herein, including but not limited to: sample partitioning, sample separation, binding reactions, fragmentation (e.g., before partitioning or after partitioning), ligation reactions, and other enzymatic reactions.
The device may also be used in a variety of different molecular biology applications, including but not limited to: nucleic acid sequencing, protein sequencing, nucleic acid quantification, sequencing optimization, detection of gene expression, quantification of gene expression, and single cell analysis of genomic or expressed markers. Furthermore, the device has many medical applications. For example, it can be used for the identification, detection, diagnosis, treatment, staging or risk prediction of a variety of genetic and non-genetic diseases and disorders, including cancer.
Microcapsules II
Fig. 1A is a schematic illustration of an exemplary microcapsule comprising an internal compartment 120 encapsulated by a second layer 130, the second layer 130 being encapsulated by a solid or semi-permeable shell or membrane 110. Typically, the shell separates the interior compartments from their immediate environment (e.g., the interior of the microwells). The interior compartments, e.g., 120, 130, may contain materials, e.g., reagents. As shown in fig. 1A, reagent 100 may be present in interior compartment 120. However, in some cases, the reagent is located in the encapsulation layer 130 or in both compartments. Generally, the microcapsules may release the inner material or a portion thereof upon introduction of a particular trigger. This triggering may result in the destruction of the shell layer 110 and/or the inner encapsulation layer 130, thereby bringing the interior compartment 100, 120 into contact with the external environment, such as the cavity of a microwell.
The microcapsules may comprise several fluid phases and may comprise emulsions (e.g., water-in-oil emulsions, oil-in-water emulsions). The microcapsules may comprise an inner layer 120 that is immiscible with a second layer 130 encapsulating the inner layer. For example, inner layer 120 may comprise an aqueous fluid, while encapsulating layer 130 may be a non-aqueous fluid, such as an oil. Conversely, inner layer 120 may comprise a non-aqueous fluid (e.g., oil) and encapsulating layer 130 may comprise an aqueous fluid. In some cases, the microcapsules do not comprise a second encapsulant layer. Typically, the microcapsules are further encapsulated by a shell layer 110, which shell layer 110 may comprise a polymeric material. In some cases, the microcapsules may comprise droplets. In some cases, the microcapsules may be microdroplets.
Droplets and droplet generation methods are described, for example, in U.S. patent RE41,780, which is incorporated herein by reference in its entirety for all purposes. The device may also contain a microfluidic element that enables the flow of samples and/or microcapsules through the device and the distribution of the samples and/or microcapsules within the partitions.
The microcapsule may comprise a plurality of compartments. The microcapsule may comprise at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 50, 100, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 10000, or 50000 compartments. In other cases, the microcapsule comprises less than 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 50, 100, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 10000, or 50000 compartments. Similarly, each compartment or a subset thereof may also be subdivided into a plurality of additional compartments. In some cases, each compartment, or a subset thereof, is subdivided into at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 50, 100, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 10000, or 50000 compartments. In other cases, each compartment, or a subset thereof, is further subdivided into less than 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 50, 100, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 6500, 7000, 7500, 8000, 8500, 9000, 9500, 10000, or 50000 compartments.
There are a number of possible distributions of reagents in the various compartments. For example, each compartment (or a certain percentage of the total number of compartments) may contain the same reagent or the same combination of reagents. In some cases, each compartment (or some percentage of the total number of compartments) contains a different reagent or a different combination of reagents.
The compartments may be configured in a variety of ways. In some cases, the microcapsules may comprise a plurality of concentric compartments (repeating units of compartments comprising the preceding compartments) typically separated by immiscible layers. In such microcapsules, the reagent may be present in alternating compartments, every third compartment, or every fourth compartment.
In some cases, most of the compartments with microcapsules are not concentric; rather, they exist as separate, self-contained entities within the microcapsules. Fig. 1B shows an example of a microcapsule comprising a plurality of
The microcapsules may comprise one polymeric shell (see, e.g., fig. 1 and 2) or multiple polymeric shells. For example, the microcapsules may comprise multiple polymeric shells layered on top of each other. In other cases, a single compartment within the microcapsule comprises a polymeric shell, or a portion of the compartments may comprise a polymeric shell. For example, all or a portion of the
The microcapsule component of the devices of the present disclosure may provide controlled and/or timed release of reagents for sample preparation of analytes. Microcapsules are particularly useful for the controlled release and transport of different types of chemicals, ingredients, pharmaceuticals, fragrances and the like, these including in particular sensitive agents such as enzymes and proteins (see, e.g., d.d. lewis, "biodegradablephydrolymes and Drug Delivery Systems", m.chansin and r.langer eds (Marcel Decker, new york, 1990); j.p.mcgee et al, j.control.release 34(1995), 77).
Microcapsules may also provide a means (means) to deliver the agent in discrete and definable amounts. Microcapsules can be used to prevent premature mixing of the reagent with the sample by separating the reagent from the sample. Microcapsules may also facilitate handling and limit contact with particularly sensitive reagents such as enzymes, nucleic acids, and other chemicals used in sample preparation.
A. Preparation of microcapsules
The microcapsules of the devices of the present disclosure can be prepared by a variety of methods and processes. The preparation technology can comprise the following steps: pan coating, spray drying, centrifugal extrusion, emulsion-based methods, and/or microfluidics. In general, the method of preparation is selected based on the desired properties of the microcapsules. For example, shell wall thickness, permeability, chemical composition of the shell wall, mechanical integrity of the shell wall, and capsule size may be considered when selecting a method. The choice of preparation method may also be based on the ability to introduce specific materials into the capsule, such as whether the core material (e.g., fluid, reagent, etc.) is aqueous, organic, or inorganic. In addition, the method of preparation may affect the shape and size of the microcapsules. For example, the shape of the capsules (e.g., spherical, elliptical, etc.) may depend on the shape of the droplets in the precursor liquid, which may depend on the viscosity and surface tension of the core liquid, the flow direction of the emulsion, the choice of surfactant used in droplet stabilization, and physical limitations, such as preparation in microchannels or capillaries having particular dimensions (e.g., dimensions that require deformation of the microcapsules so that they fit in the microchannel or capillary).
The microcapsules may be prepared by emulsion polymerization, which is a method of: wherein the monomer units polymerize at the water/organic interface in the emulsion to form the shell. The reagents are mixed with the aqueous phase of the biphasic mixture. Vigorous shaking or sonication of the mixture produces droplets containing the reagents, which are surrounded by a polymeric shell.
In some cases, microcapsules can be prepared by layer-by-layer assembly, which is a process that: wherein negatively and positively charged polyelectrolytes are deposited onto particles, such as metal oxide cores. Electrostatic interactions between polyelectrolytes produce a polymeric shell around the core. Subsequently, the core can be removed by the addition of an acid, resulting in semi-permeable hollow spheres that can be loaded with multiple agents.
In yet a further case, the microcapsules may be prepared by coacervation, coacervation being one such method: wherein two oppositely charged polymers are entangled in an aqueous solution to form a neutralized polymeric shell wall. One polymer may be contained in the oil phase and another polymer of opposite charge contained in the water phase. This aqueous phase may contain the reagent to be encapsulated. Attraction of one polymer to another can lead to the formation of agglomerates. In some embodiments, gelatin and gum arabic are ingredients of such a preparation method.
Microcapsules can also be prepared by internal phase separation, which is a process that: wherein the polymer is dissolved in a solvent mixture comprising volatile and non-volatile solvents. Droplets of the resulting solution are suspended in an aqueous layer, which is stabilized by continuous stirring and the use of surfactants. This phase may contain the agent to be encapsulated. As the volatile solvent evaporates, the polymer coalesces to form the shell wall. In some cases, polymers such as polystyrene, poly (methyl methacrylate), and poly (tetrahydrofuran) are used to form the shell wall.
Microcapsules can also be prepared by flow focusing methods, which is one such method: wherein a microcapillary device is used to generate a double emulsion comprising a single inner droplet enclosed in an intermediate fluid which is then dispersed to an outer fluid. The inner droplet may contain the reagent to be encapsulated. The intermediate fluid becomes a shell wall that can be formed by a cross-linking reaction.
B. Microcapsule composition
Microcapsules may comprise a variety of materials having a wide range of chemical properties. Typically, the microcapsules comprise a material having the ability to form microcapsules of a desired shape and size, and which is compatible with the reagents to be stored in the microcapsules.
The microcapsules may comprise a wide variety of different polymers including, but not limited to: a polymer, a thermosensitive polymer, a photosensitive polymer, a magnetic polymer, a pH-sensitive polymer, a salt-sensitive polymer, a chemosensitive polymer, a polyelectrolyte, a polysaccharide, a peptide, a protein, and/or a plastic. The polymer may include, but is not limited to, materials such as: poly (N-isopropylacrylamide) (PNIPAAm), poly (styrene sulfonate) (PSS), poly (allylamine) (PAAm), poly (acrylic acid) (PAA), poly (ethylenimine) (PEI), poly (diallyldimethyl-ammonium chloride) (PDADMAC), poly (pyrrole) (poly (pyrolle)) (PPy), poly (vinylpyrrolidone) (PVPON), poly (vinylpyridine) (PVP), poly (methacrylic acid) (PMAA), poly (methyl methacrylate) (PMMA), Polystyrene (PS), poly (tetrahydrofuran) (PTHF), poly (phthalaldehyde) (PTHF), poly (hexylviologen) (PHV), poly (L-lysine) (PLL), poly (L-arginine) (PARG), poly (lactic-glycolic acid) copolymer (PLGA).
In general, the materials used for the microcapsules, particularly the shell of the microcapsules, may enable the microcapsules to rupture upon application of a stimulus. For example, microcapsules may be prepared from heat-sensitive polymers and/or may comprise one or more shells containing such heat-sensitive polymers. The thermosensitive polymer may be stable under conditions for storage or loading. When exposed to heat, the heat-sensitive polymer component may undergo depolymerization, resulting in a disruption of the shell integrity and release of the interior material of the microcapsule (and/or interior microcapsule) to the external environment (e.g., the interior of the micropores). Exemplary thermosensitive polymers may include, but are not limited to, NIPAAm or PNIPAM hydrogels. The microcapsules may also contain one or more types of oils. Exemplary oils include, but are not limited to, hydrocarbon oils, fluorinated oils, fluorocarbon oils, silicone oils, mineral oils, vegetable oils, and any other suitable oils.
The microcapsules may also contain a surfactant, such as an emulsifying surfactant. Exemplary surfactants include, but are not limited to, cationic surfactants, nonionic surfactants, anionic surfactants, hydrocarbon surfactants, or fluorosurfactants. The surfactant may improve the stability of one or more components of the microcapsule, such as the oil-containing internal compartment.
Additionally, the microcapsules may comprise an inner material that is miscible with the material outside the capsule. For example, the inner material may be an aqueous fluid and the sample within the microwells may also be in the aqueous fluid. In other examples, the microcapsules may comprise powders or nanoparticles that are miscible with the aqueous fluid. For example, the microcapsules may contain such powders or nanoparticles within the internal compartment. When the microcapsules are ruptured, such powders or nanoparticles are released to the external environment (e.g., the interior of the micropores) and may be mixed with an aqueous fluid (e.g., an aqueous sample fluid).
Additionally, the microcapsules may contain materials that are immiscible with the surrounding environment (e.g., the interior of the micropores, the sample fluid). In such cases, phase separation between the inner and outer components may facilitate mixing, such as mixing of the inner component with the surrounding fluid, when the inner emulsion is released to the surrounding environment. In some cases, when the microcapsules are triggered to release their contents, pressure or force is also released, which facilitates mixing of the inner component with the outer component.
The microcapsules may also contain a polymer within the interior of the capsule. In some cases, such polymers may be porous polymer beads that can capture a reagent or combination of reagents. In other cases, this polymer may be beads that have previously swelled to form a gel. Examples of polymer-based gels that can be used as the internal emulsion of the capsule can include, but are not limited to, sodium alginate gels or polyacrylamide gels swollen with oligonucleotide barcodes or the like.
In some cases, the microcapsules can be gel beads comprising any of the polymer-based gels described herein. For example, gel bead microcapsules may be formed by encapsulating one or more polymer precursors in microdroplets. Gel beads can be produced when the polymer precursor is exposed to an accelerator, such as Tetramethylethylenediamine (TEMED).
Analytes and/or reagents, such as oligonucleotide barcodes, for example, may be coupled/immobilized to the inner surface of a gel bead (e.g., the interior accessible by diffusion of the oligonucleotide barcode and/or the material used to generate the oligonucleotide barcode) and/or the outer surface of a gel bead or any other microcapsule described herein. The coupling/immobilization may be by any form of chemical bonding (e.g., covalent, ionic) or physical phenomenon (e.g., van der waals forces, dipole-dipole interactions, etc.). In some cases, the coupling/immobilization of the agent onto the gel bead or any other microcapsule described herein may be reversible, e.g., by an unstable moiety (e.g., by a chemical cross-linker, including chemical cross-linkers described herein). Upon application of a stimulus, the labile moiety can cleave and allow release of the immobilized reagent. In some cases, the labile moiety is a disulfide bond. For example, where the oligonucleotide barcodes are immobilized to the gel beads by disulfide bonds, exposure of the disulfide bonds to a reducing agent may cleave the disulfide bonds and release the oligonucleotide barcodes from the beads. The labile moiety may be included as part of the gel bead or microcapsule, as part of a chemical linker attaching the reagent or analyte to the gel bead or microcapsule, and/or as part of the reagent or analyte.
The gel beads or any other type of microcapsules described herein may contain different amounts of reagents. The reagent density of each microcapsule may vary depending on the particular microcapsule and the particular reagent used. For example, the microcapsule or gel bead may comprise at least about 1, 10, 100, 1,000, 10,000, 100,000, 1,000,000, 5,000,000, 10,000,000, 50,000,000, 100,000,000, 500,000,000, or 1,000,000,000 oligonucleotide barcodes per microcapsule or gel bead. The gel beads may comprise the same oligonucleotide barcode or may comprise different oligonucleotide barcodes.
In other examples, the microcapsules may contain one or more materials that produce a net neutral, negative, or positive charge on the shell walls of the capsule. In some cases, the charge of the capsule may help prevent or promote aggregation or clustering of particles, or attachment to or repulsion from a portion of the device.
Further, the microcapsules may comprise one or more materials that render the shell wall of the capsule hydrophilic or hydrophobic. A hydrophilic material that may be used for the capsule wall may be poly (N-isopropylacrylamide). A hydrophobic material that may be used for the capsule wall may be polystyrene. In some cases, the hydrophilic shell wall can facilitate wicking of the capsule into the pores containing the aqueous fluid.
C. Size and shape of microcapsules
The microcapsules can have any of a number of sizes or shapes. In some cases, the shape of the microcapsules may be spherical, ellipsoidal, cylindrical, hexagonal, or any other symmetrical or asymmetrical shape. Any cross-section of the microcapsules may also have any suitable shape, including but not limited to: circular, oval, square, rectangular, hexagonal, or other symmetrical or asymmetrical shapes. In some cases, the microcapsules may have a specific shape that is complementary to the opening (e.g., the surface of the micropores) of the device. For example, the microcapsules may be spherical and the openings of the micropores of the device may be circular.
The microcapsules may be of uniform size (e.g., all of the microcapsules are of the same size) or of non-uniform size (e.g., some of the microcapsules are of different sizes). The microcapsules can have a size (e.g., diameter, cross-section, sides, etc.) of at least about 0.001 μm, 0.01 μm, 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, or 1 nm. In some cases, the microcapsules comprise micropores of up to about 0.001 μm, 0.01 μm, 0.1 μm, 0.5 μm, 1 μm, 5 μm, 10 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, or 1 nm.
In some cases, the microcapsules have a size and/or shape such that a limited number of microcapsules are deposited in a single partition (e.g., microwell, microdroplet) of the microcapsule array. The microcapsules may be of a particular size and/or shape such that exactly or no more than 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 capsules fit into a single microwell; in some cases, an average of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 capsules fit into a single microwell. In still further cases, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 100, 500, or 1000 capsules fit into a single microwell.
D. Reagent and reagent loading
The devices provided herein can comprise free reagents and/or reagents encapsulated in microcapsules. The reagents may be various molecules, chemicals, particles and elements suitable for sample preparation reactions of analytes. For example, microcapsules used in a sample preparation reaction for DNA sequencing of a target may comprise one or more of the following reagents: enzymes, restriction enzymes (e.g., multiple cutters), ligases, polymerases (e.g., polymerases that recognize and do not recognize dUTP and/or uracil), fluorophores, oligonucleotide barcodes, buffers, deoxynucleotide triphosphates (dntps) (e.g., deoxyadenosine triphosphate (dATP), deoxycytidine triphosphate (dCTP), deoxyguanosine triphosphate (dGTP), deoxythymidine triphosphate (dTTP), deoxyuridine triphosphate (dUTP)), deoxynucleotide triphosphates (ddntps), and the like. In another example, microcapsules used in a sample preparation reaction for single cell analysis may contain reagents, such as one or more of the following: lysis buffers, detergents, fluorophores, oligonucleotide barcodes, ligases, proteases, heat-activatable proteases, protease or nuclease inhibitors, buffers, enzymes, antibodies, nanoparticles, and the like.
Exemplary agents include, but are not limited to: buffer, acidic solution, basic solution, temperature-sensitive enzyme, pH-sensitive enzyme, photosensitive enzyme, metal ion, magnesium chloride, sodium chloride, manganese, aqueous buffer, mild buffer, ionic buffer, inhibitor, enzyme, protein, nucleic acid, antibody, saccharide, lipid, oil, salt, ion, detergent, ionic detergent, non-ionic detergent, oligonucleotide, nucleotide, dNTP, ddNTP, deoxyribonucleic acid (DNA), ribonucleic acid (RNA), peptide nucleic acid, circular DNA (cdna), double-stranded DNA (dsdna), single-stranded DNA (ssdna), plasmid DNA, cosmid DNA, chromosomal DNA, genomic DNA (gdna), viral DNA, bacterial DNA, mtDNA (mitochondrial DNA), messenger RNA (mrna), ribosomal RNA (rrna), transfer RNA (trna), nRNA, short interfering RNA (sirna), small nuclear RNA (snrna), small nuclear RNA (snohna), small Cajul-specific RNA (scaarna, or RNA, micrornas, double-stranded RNAs (dsrna), ribozymes, riboswitches and viral RNAs, polymerases (e.g., polymerases that recognize and do not recognize dUTP and/or uracil), ligases, restriction enzymes, proteases, nucleases, protease inhibitors, nuclease inhibitors, chelators, reducing agents (e.g., Dithiothreitol (DTT), 2-tris (2-carboxyethyl) phosphine (TCEP)), oxidizing agents, fluorophores, probes, chromophores, dyes, organics, emulsifiers, surfactants, stabilizers, polymers, water, small molecules, drugs, radioactive molecules, preservatives, antibiotics, aptamers, and pharmaceutical compounds.
In some cases, the microcapsules contain a set of reagents (e.g., a set of enzymes, a set of minerals, a set of oligonucleotides, a mixture of different barcodes, a mixture of the same barcodes) with similar properties. In other cases, the microcapsules contain a heterogeneous mixture of reagents. In some cases, the heterogeneous mixture of reagents contains all the components necessary to carry out the reaction. In some cases, such mixtures contain all of the components necessary to carry out the reaction, except 1, 2, 3, 4, 5 or more of the components necessary to carry out the reaction. In some cases, such additional components are contained in solutions within different microcapsules or within partitions (e.g., micropores) of the device.
The reagents may be preloaded into the device (e.g., prior to introduction of the analyte) or post-loaded into the device. They can be loaded directly into the device; alternatively, in some cases, the reagents are encapsulated within microcapsules loaded into the device. In some cases, only microcapsules containing the agent are introduced. In other cases, both the free reagent and the reagent encapsulated in the microcapsule are loaded into the device either sequentially or simultaneously. In some cases, the reagents are introduced to the device before or after a particular step. For example, lysis buffer reagents can be introduced into the device after the cell sample is partitioned into multiple partitions (e.g., microwells, microdroplets) within the device. In some cases, the reagents and/or microcapsules containing the reagents are introduced sequentially, such that different reactions or operations occur at different steps. The reagents (or microcapsules) may also be loaded during the step interspersed with the reaction or manipulation step. For example, microcapsules comprising reagents for fragmenting molecules (e.g., nucleic acids) can be loaded into a device, followed by a fragmentation step, after which microcapsules comprising reagents for attaching barcodes (or other unique identifiers, such as antibodies) can be loaded, followed by attaching barcodes to the fragmented molecules. Other methods of loading reagents are further described elsewhere herein.
E. Molecular "Bar code"
It may be desirable to retain the option of identifying and tracking individual molecules or analytes after or during sample preparation. In some cases, one or more unique molecular identifiers (sometimes referred to in the art as "molecular barcodes") are used as sample preparation reagents. These molecules may comprise a variety of different forms, such as oligonucleotide barcodes, antibodies or antibody fragments, fluorophores, nanoparticles, and other elements, or combinations thereof. Depending on the particular application, the molecular barcode may bind reversibly or irreversibly to the target analyte and allow identification and/or quantification of individual analytes after sample preparation and recovery from the device.
The devices of the present disclosure may be adapted for use in nucleic acid sequencing, protein detection, single molecule analysis, and other methods that require: a) precise measurement of the presence and amount of a particular analyte, b) multiplex reactions in which multiple analytes are combined for analysis. The devices of the present disclosure may employ microwells or other types of partitions (e.g., microdroplets) of a microwell array to physically partition a target analyte. This physical segmentation allows a single analyte to acquire one or more molecular barcodes. After sample preparation, individual analytes can be combined or combined and extracted from the device for multiplex analysis. For most applications, multiplex analysis greatly reduces the cost of the analysis and increases the throughput of the process, for example in the case of nucleic acid sequencing. Molecular barcodes may allow identification and quantification of individual molecules even after multiple analytes are combined. For example, for nucleic acid sequencing, molecular barcodes may allow sequencing of a single nucleic acid even after multiple different nucleic acids are pooled.
In some cases, oligonucleotide barcodes may be particularly useful for nucleic acid sequencing. In general, an oligonucleotide barcode may comprise a unique sequence (e.g., a barcode sequence) that confers its identifying function to the oligonucleotide barcode. The unique sequence may be random or non-random. Attachment of a barcode sequence to a nucleic acid of interest can correlate the barcode sequence to the nucleic acid of interest. The barcode can then be used to identify the nucleic acid of interest during sequencing, even when other nucleic acids of interest (e.g., comprising different barcodes) are present. In the case of fragmenting the nucleic acid of interest prior to sequencing, the attached barcode can be used to identify the fragment as belonging to the nucleic acid of interest during the sequencing process.
The oligonucleotide barcode may consist of only unique barcode sequences, or may be included as part of an oligonucleotide of longer sequence length. Such oligonucleotides may be adapters (adaptors) required for specific sequencing chemistries and/or methods. For example, such adapters may include, in addition to oligonucleotide barcodes: immobilization of the adapter (e.g., by hybridization) to a desired region of an immobilized sequence on a solid surface (e.g., a solid surface in a flow cell channel of a sequencer); sequencing the region of sequence required for binding of the primer; and/or random sequences (e.g., random N-mers) that can be used, for example, in random amplification schemes. For example, the adapter can be attached to the nucleic acid to be sequenced by amplification, ligation, or any other method described herein.
In addition, the oligonucleotide barcode and/or the larger oligonucleotide comprising the oligonucleotide barcode may comprise a natural nucleobase and/or may comprise a non-natural nucleobase. For example, where the oligonucleotide barcode or a larger oligonucleotide comprising the oligonucleotide barcode is DNA, the oligonucleotide may comprise the natural DNA bases adenine, guanine, cytosine, and thymine, and/or may comprise non-natural bases, such as uracil.
F. Microcapsule preparation for micropore loading
After preparation, the reagent-loaded microcapsules can be loaded into the device using a variety of methods. In some cases, the microcapsules may be loaded as "dry capsules. After preparation, the capsules can be separated from the liquid phase using a variety of techniques including, but not limited to, differential centrifugation, liquid phase evaporation, chromatography, filtration, and the like. The "dry capsules" may be collected as a powder or particulate matter and then deposited into the microwells of a microwell array. Loading "dry capsules" may be the preferred method in cases where loading of "wet capsules" results in loading inefficiencies, such as voids and poor distribution of microcapsules throughout the microwell array.
The reagent-loaded microcapsules may also be loaded into the device when the microcapsules are in the liquid phase, and thus loaded as "wet capsules". In some cases, the microcapsules may be suspended in a volatile oil so that the oil can be removed or evaporated, leaving only dry capsules in the pores. In some cases where loading of dry capsules results in loading inefficiencies, such as clustering, aggregation of microcapsules, and poor distribution of microcapsules throughout the microwell array, loading "wet capsules" may be the preferred method. Other methods of loading reagents and microcapsules are described elsewhere in this disclosure.
The microcapsules may also have a specific density. In some cases, the microcapsules are less dense than the aqueous fluid (e.g., water); in some cases, the microcapsules are denser than the aqueous fluid (e.g., water). In thatIn some cases, the microcapsules are less dense than the non-aqueous fluid (e.g., oil); in some cases, the microcapsules are denser than the non-aqueous fluid (e.g., oil). The microcapsules may have at least about 0.05g/cm3、0.1cm3、0.2g/cm3、0.3g/cm3、0.4g/cm3、0.5g/cm3、0.6g/cm3、0.7g/cm3、0.8g/cm3、0.81g/cm3、0.82g/cm3、0.83g/cm3、0.84g/cm3、0.85g/cm3、0.86g/cm3、0.87g/cm3、0.88g/cm3、0.89g/cm3、0.90g/cm3、0.91g/cm3、0.92g/cm3、0.93g/cm3、0.94g/cm3、0.95g/cm3、0.96g/cm3、0.97g/cm3、0.98g/cm3、0.99g/cm3、1.00g/cm3、1.05g/cm3、1.1g/cm3、1.2g/cm3、1.3g/cm3、1.4g/cm3、1.5g/cm3、1.6g/cm3、1.7g/cm3、1.8g/cm3、1.9g/cm3、2.0g/cm3、2.1g/cm3、2.2g/cm3、2.3g/cm3、2.4g/cm3Or 2.5g/cm3The density of (c). In other cases, the density of the microcapsules may be up to about 0.7g/cm3、0.8g/cm3、0.81g/cm3、0.82g/cm3、0.83g/cm3、0.84g/cm3、0.85g/cm3、0.86g/cm3、0.87g/cm3、0.88g/cm3、0.89g/cm3、0.90g/cm3、0.91g/cm3、0.92g/cm3、0.93g/cm3、0.94g/cm3、0.95g/cm3、0.96g/cm3、0.97g/cm3、0.98g/cm3、0.99g/cm3、1.00g/cm3、1.05g/cm3、1.1g/cm3、1.2g/cm3、1.3g/cm3、1.4g/cm3、1.5g/cm3、1.6g/cm3、1.7g/cm3、1.8g/cm3、1.9g/cm3、2.0g/cm3、2.1g/cm3、2.2g/cm3、2.3g/cm3、2.4g/cm3Or 2.5g/cm3. Such density may reflect the density of the microcapsules in any particular fluid (e.g., aqueous, water, oil, etc.).
Microwell array
A. Structure/feature
The device of the present disclosure may be a microwell array comprising a solid plate comprising a plurality of wells, cavities, or microwells having microcapsules and/or analytes deposited therein. Typically, a fluid sample (or analyte) is introduced into the device (e.g., through an inlet) and then travels through a flow channel that distributes the sample into a plurality of microwells. In some cases, additional fluid is also introduced into the device. The microwells may contain microcapsules when the sample is introduced; alternatively, in some cases, the microcapsules are introduced into the microwells after the sample is introduced.
FIG. 2A shows a prototype of a microwell array; fig. 2B shows a side view. The microwell array may comprise a
The microwell array may comprise inlets (200 and 240) and/or outlets (210 and 260); in some cases, the microwell array comprises a plurality of inlets and/or outlets. The sample (or analyte) or microcapsules may be introduced into the device via the inlet. Solutions containing analytes, reagents and/or microcapsules can be added manually to
In some cases, the solution containing the microcapsules and/or analyte may be pulled through the device via a vacuum manifold attached to the
The volume of each hole may be a measure of the height of the hole (thickness of the plate) and the effective diameter of each hole. The capacity of a single well may be selected from a plurality of volumes. In some cases, the device can comprise a well (or microwell) having a capacity of at least 0.001fL, 0.01fL, 0.1fL, 0.5fL, 1fL, 5fL, 10fL, 50fL, 100fL, 200fL, 300fL, 400fL, 500fL, 600fL, 700fL, 800fL, 900fL, 1pL, 5pL, 10pL, 50pL, 100pL, 200pL, 300pL, 400pL, 500pL, 600pL, 700pL, 800pL, 900pL, 1nL, 5nL, 10nL, 50nL, 100nL, 200nL, 300nL, 400nL, 500nL, 600 nL, 700pL, 800 nL, 900 nL, 1nL, 5nL, 10nL, 50nL, 100nL, 200nL, 300nL, 400nL, 500nL, 1uL, 50uL, or 100 uL. In other cases, the microcapsule comprises pores of less than 0.001fL, 0.01fL, 0.1fL, 0.5L, 5fL, 10fL, 50fL, 100fL, 200fL, 300fL, 400fL, 500fL, 600fL, 700fL, 800fL, 900fL, 1pL, 5pL, 10pL, 50pL, 100pL, 200pL, 300pL, 400pL, 500pL, 600pL, 700pL, 800pL, 900pL, 1nL, 5nL, 10nL, 50nL, 100nL, 200nL, 300nL, 400nL, 500nL, 1uL, 50uL, or 100 uL.
There may be variability in the volume of fluid in different microwells in the array. More specifically, the volume of different microwells may vary by at least (or at most) + or-1%, 2%, 3%, 4%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200%, 300%, 400%, 500%, or 1000% among a group of microwells. For example, the microwell may contain a fluid volume that is at most 80% of the fluid volume within the second microwell.
The microwell array may comprise a range of pore densities based on the size of the individual microwells and the size of the plate. In some examples, the plurality of micropores can have at least about 2,500 pores/cm2At least about 1,000 pores/cm2The density of (c). In some cases, the plurality of wells can have at least 10 wells/cm2The density of (c). In other cases, the pore density can include at least 10 pores/cm250 wells/cm2100 wells/cm2500 wells/cm21000 wells/cm25000 holes/cm210000 wells/cm250000 holes/cm2Or 100000 holes/cm2. In other cases, the pore density can be less than 100000 pores/cm210000 wells/cm25000 holes/cm21000 wells/cm2500 wells/cm2Or 100 holes/cm2。
In some cases, the interior surfaces of the microwells comprise a hydrophilic material that preferably holds an aqueous sample; in some cases, the regions between the microwells are comprised of a hydrophobic material that can preferentially attract the hydrophobic sealing fluid described herein.
Multiple microwell arrays, such as fig. 2B, may be arranged within a single device. Fig. 3, 300. For example, discrete microwell array slides may be arranged in parallel on a plate support. In some cases, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 25, 50, or 100 microwell arrays are arranged in parallel. In other cases, up to 100, 50, 25, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 devices are arranged in parallel.
The array of microwells in a common device can be operated simultaneously or sequentially. For example, the arrayed devices may be loaded with samples or capsules simultaneously or sequentially.
B. Microwell array fluids
The microwell array can comprise any number of different fluids, including aqueous, non-aqueous, oil, and organic solvents, such as alcohols. In some cases, the fluid is used to carry components such as reagents, microcapsules, or analytes to a target location, such as a microwell, an outlet port, or the like. In other cases, the fluid is used to flush the system. In other cases, the fluid may be used to seal the pores.
Any fluid or buffer that is physiologically compatible with the analyte (e.g., cells, molecules) or reagents used in the device may be used. In some cases, the fluid is aqueous (buffered or unbuffered). For example, a sample comprising a population of cells suspended in a buffered aqueous solution can be introduced into a microwell array, flowed through the device, and distributed to microwells. In other cases, the fluid flowing through the device is non-aqueous (e.g., oil). Exemplary non-aqueous fluids include, but are not limited to: oils, non-polar solvents, hydrocarbon oils, decanes (e.g., tetradecane or hexadecane), fluorocarbon oils, fluorinated oils, silicone oils, mineral oils, or other oils.
Typically, the microcapsules are suspended in a fluid that is compatible with the components of the shell of the microcapsules. Fluids including, but not limited to, water, alcohols, hydrocarbon oils, or fluorocarbon oils are particularly useful fluids for suspending and flowing microcapsules through a microarray device.
C. Further segmentation and sealing
After the analytes, free reagents, and/or microcapsules are loaded into the device and distributed to the microwells, they may be further partitioned or separated within the microwells using a sealing fluid. Sealing fluids may also be used to seal individual apertures. The sealing fluid may be introduced through the same inlet port used for introducing the analyte, reagent and/or microcapsules. In some cases, however, the sealing fluid is introduced into the device through a single inlet port or through multiple separate inlet ports.
Typically, the sealing fluid is a non-aqueous fluid (e.g., oil). As the sealing fluid flows through the microwell array device, it can displace excess aqueous solution (e.g., a solution containing analyte, free reagents, and/or microcapsules) from individual microwells, thereby potentially removing aqueous bridging between adjacent microwells. The pores described herein may themselves comprise a hydrophilic material capable of wicking aqueous fluid (e.g., sample fluid, microcapsule fluid) into the individual pores. In some cases, the region outside the pores comprises a hydrophobic material, again to facilitate positioning of the aqueous fluid to the interior of the micropores.
The sealing fluid may remain in the device or be removed. The sealing fluid may be removed, for example, by flowing through the outlet port. In other cases, the sealing oil may comprise a volatile oil that can be removed by the application of heat. Once the sealing fluid is removed, the analytes, free reagents, and/or microcapsules may be physically separated from each other in the microwells.
The fluid may be selected such that its density is equal to, greater than, or less than the density of the microcapsules. For example, the microcapsules may have a density greater than the aqueous fluid encapsulating the oil and/or sample and reagents, thereby enabling the microcapsules to remain in the pores as the encapsulating oil flows through the device. In another example, the density of the capsules may be less than the density of the aqueous fluid of the sample or the fluid in which the microcapsules are suspended as described herein, thereby facilitating movement and distribution of the capsules in the plurality of micropores of the device.
In the case of microcapsules containing paramagnetic materials, a magnetic field may be used to load or guide the capsules into the micropores. The magnetic field may also be used to retain such microcapsules within the pores while filling the pores with sample, reagents, and/or sealing fluids. The magnetic field may also be used to remove the capsule shell from the well, particularly after the capsule is ruptured.
In some cases, the sealing fluid may remain therein when operating or reacting within the microwells. The presence of the sealing fluid may be used to further divide, separate or seal individual microwells. In other cases, the encapsulating fluid may serve as a carrier for the microcapsules. For example, an encapsulating fluid containing microcapsules may be introduced into the device to facilitate distribution of the microcapsules to individual micropores. For such applications, the encapsulating fluid may be denser than the microcapsules to promote more uniform distribution of the microcapsules into the micropores. Upon application of a stimulus, microcapsules within the encapsulated fluid may release the agent to the micropores. In some cases, the sealing fluid may contain a chemical or other agent capable of traveling from the sealing fluid to the pores (e.g., by leaching or other mechanism) and triggering rupture of the capsules, where the capsules are present within the pores or within the sealing fluid.
Methods other than those involving sealing fluids may also be used to seal the microwells after loading with analytes, free reagents, and/or microcapsules. For example, the microwells may be sealed with a laminate, tape, plastic lid, oil, wax, or other suitable material to create an enclosed reaction chamber. The sealants described herein may prevent evaporation of the contents of the microwells or prevent other unintended consequences of the reaction or operation. It may be particularly desirable to prevent evaporation when heat is applied to the device, for example, when heat is applied to stimulate microcapsule release.
In some cases, the laminate seal may also allow for the retrieval of contents from a single hole. In this case, one well of interest may be unsealed (e.g., sealed by removing the laminate) at a given time to enable further analysis of the analyte, for example by MALDI mass spectrometry. Such applications are useful in many settings, including high throughput drug screening.
IV. Loading step
As described herein, analytes, free reagents, and/or microcapsules may be loaded into the devices of the present invention in any suitable manner or order. The loading may be random or non-random. In some cases, the exact number of analytes and/or microcapsules are loaded into each individual microwell. In some cases, the exact number of analytes and/or microcapsules are loaded into specific portions of the microwells in the plate. In still other cases, an average number of analytes and/or microcapsules are loaded into each individual microwell. Furthermore, as described herein, in some cases, "dry" microcapsules are loaded into the device, while in other cases, "wet" microcapsules are loaded into the device. In some cases, a combination of "dry" and "wet" microcapsules and/or reagents are loaded into the device simultaneously or sequentially.
As mentioned herein, the loading of the device may be performed in any order and may be performed in multiple stages. In some cases, the microcapsules are preloaded into the device prior to loading the analyte. In other cases, the microcapsules and analyte are loaded simultaneously. In still other cases, the analyte is loaded prior to loading the microcapsules.
The microcapsules and/or analytes may be loaded in multiple stages or multiple times. For example, the microcapsules may be loaded into the device both before and after the analyte is loaded into the device. The microcapsules that are preloaded (e.g., loaded prior to introduction of the analyte) can contain the same reagents as the microcapsules loaded after introduction of the analyte. In other cases, the preloaded microcapsules contain a different reagent than the reagent within the microcapsules loaded upon introduction of the analyte. In some cases, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, or 20 different sets of microcapsules are loaded onto the device. In some cases, the different sets of microcapsules are loaded sequentially; alternatively, different sets of microcapsules may be loaded simultaneously. Similarly, multiple sets of analytes may be loaded into the device. In some cases, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, or 20 different sets of analytes are loaded onto the device. In some cases, different sets of analytes are sequentially loaded; alternatively, different sets of analytes may be loaded simultaneously.
The present disclosure provides devices that contain a number of microcapsules and/or analytes loaded per well. In some cases, up to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 75, or 100 microcapsules and/or analytes are loaded into each individual microwell. In some cases, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 75, or 100 microcapsules and/or analytes are loaded into each individual microwell. In some cases, on average, up to 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 75, or 100 microcapsules and/or analytes are loaded into each individual microwell. In other cases, on average, at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 75, or 100 microcapsules and/or analytes are loaded into each individual microwell. In some cases, about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 75, or 100 microcapsules and/or analytes are loaded into each individual microwell.
The analyte and/or microcapsules may be applied in an amount that allows the desired number of analytes to be deposited into a single microwell. For example, the final dilution of the analyte (such as a cell) may achieve loading of one cell per microwell or any desired number of analytes per microwell. In some cases, the poisson distribution is used to guide or predict the final concentration of analyte or microcapsules in each well.
The microcapsules may be loaded into the microarray device in a specific pattern. For example, some portions of the device may comprise microcapsules containing a particular reagent (e.g., a unique barcode, an enzyme, an antibody subclass, etc.), while other portions of the device may comprise microcapsules containing a different reagent (e.g., a different barcode, a different enzyme, a different antibody subclass, etc.). In some cases, the microcapsules in a portion of the array may contain a control reagent. For example, they may contain a positive control comprising a control analyte and the necessary materials for the reaction. Alternatively, in some cases, the microcapsules contain a negative control reagent, such as an inactivated enzyme or a synthetic oligonucleotide sequence that is resistant to fragmentation. In some cases, the negative control reagent may control the specificity of the sample preparation reaction, etc. In other cases, a negative control microcapsule may comprise the same reagents present in other microcapsules, except that the negative control microcapsule may lack certain reagents (e.g., lysis buffer, polymerase, etc.).
The analytes/samples may also be loaded into the microarray device in a specific pattern. For example, certain portions of the device may contain a particular analyte, such as a control analyte or an analyte derived from a particular source. This can be used in combination with the specific loading of the barcode to known well locations. This feature may allow for the location-specific (mapping) on the array to be mapped to the sequencing data, thereby reducing the number of barcodes to be used for labeling reactions.
In the case of a partition into droplets, the analyte and reagent may be combined within the droplet with the aid of a microfluidic device. For example, microdroplets can be generated that comprise gel beads (e.g., gel beads comprising oligonucleotide barcodes), nucleic acid analytes, and any other desired reagents. The gel beads, nucleic acid analyte, and reagents in the aqueous phase may be combined at the intersection of two or more channels of the microfluidic device. At a second intersection of two or more channels of the microfluidic device, droplets comprising the resulting mixture may be generated by contacting an aqueous mixture of reagents, gel beads, and nucleic acid analyte with an oil continuum.
Stimulation by microcapsules
A variety of different stimuli can be used to trigger the release of the agent from the microcapsule or from the internal compartment therein. In some cases, the microcapsules are degradable. In general, the triggering may result in the rupture or degradation of the shell or membrane surrounding the microcapsule, the rupture or degradation of the interior of the microcapsule, and/or the rupture or degradation of any chemical bond that secures the agent to the microcapsule. Exemplary triggers include, but are not limited to: chemical triggers, bulk changes (bulk changes), biological triggers, optical triggers, thermal triggers, magnetic triggers, and any combination thereof. See, for example, Eser-Kahn et al (2011) Macromolecules 44: 5539-; wang et al (2009) ChemPhys Chem 10: 2405-2409.
A. Chemical stimulation and host changes
A number of chemical triggers can be used to trigger the rupture or degradation of the microcapsules. Examples of such chemical changes may include, but are not limited to, pH-mediated changes to the shell wall, disintegration of the shell wall by chemical cleavage of crosslinks, triggered depolymerization of the shell wall, and shell wall switching reactions. The host change may also be used to trigger the rupture of the microcapsules.
Changes in the pH of the solution, particularly a decrease in pH, can trigger the rupture by a number of different mechanisms. The addition of acid can cause degradation or decomposition of the shell wall by a variety of mechanisms. The addition of protons may break down cross-links of polymers in the shell wall, break ionic or hydrogen bonds in the shell wall, or create nanopores in the shell wall to allow internal contents to permeate through to the outside. In some examples, the microcapsules comprise an acid degradable chemical cross-linker, such as a ketal. A decrease in pH, particularly to a pH below 5, can induce the conversion of the ketal into a ketone and two alcohols and promote the rupture of the microcapsules. In other examples, the microcapsules may comprise one or more pH sensitive polyelectrolytes (e.g., PAA, PAAm, PSS, etc.). The lowering of pH may disrupt the ionic or hydrogen bonding interactions of such microcapsules, or create nanopores therein. In some cases, microcapsules comprising polyelectrolytes contain a charged, gel-based core that expands and contracts when pH changes.
Removal of cross-linkers (e.g., disulfide bonds) within the microcapsules can also be accomplished by a variety of mechanisms. In some examples, a variety of chemicals may be added to the solution of microcapsules that induce oxidation, reduction, or other chemical changes to the polymer component of the shell wall. In some cases, a reducing agent, such as β -mercaptoethanol, Dithiothreitol (DTT), or 2-tris (2-carboxyethyl) phosphine (TCEP), is added to break the disulfide bonds in the microcapsule shell wall. Additionally, enzymes may be added to cleave peptide bonds within the microcapsules, resulting in cleavage of the shell wall crosslinks.
Depolymerization may also be used to rupture the microcapsules. Chemical triggers can be added to facilitate removal of the protective head groups. For example, triggering may result in the removal of carbonate or carbamate head groups within the polymer, which in turn causes depolymerization and release of the agent from the interior of the capsule.
The shell wall switching reaction may be due to any structural change in the shell wall porosity. The porosity of the shell wall can be modified, for example by the addition of azo dyes or viologen derivatives. The addition of energy (e.g., electricity, light) can also be used to stimulate a change in porosity.
In yet another example, the chemical trigger may comprise an osmotic trigger, whereby a change in ion or solute concentration of the microcapsule solution induces swelling of the capsule. Swelling can cause the build-up of internal pressure, causing the capsule to rupture to release its contents.
It is also known in the art that the bulk or physical changes of the microcapsules by various stimuli also provide many advantages in designing the capsules to release the agent. The bulk or physical change occurs on a macroscopic scale, where the capsule rupture is the result of mechanical-physical forces induced by the stimulus. These methods may include, but are not limited to, pressure induced cracking, shell wall melting, or changes in shell wall porosity.
B. Biological stimulation
Biostimulation can also be used to trigger the rupture or degradation of the microcapsules. Generally, biological triggers are similar to chemical triggers, but many examples use biomolecules or molecules commonly found in living systems, such as enzymes, peptides, carbohydrates, fatty acids, nucleic acids, and the like. For example, the microcapsules may comprise a polymer with peptide cross-links that are susceptible to cleavage by a specific protease. More specifically, one example may include microcapsules comprising GFLGK peptide cross-links. Upon addition of a biological trigger such as the protease cathepsin B, the peptide cross-links of the shell wall are cleaved and the contents of the capsule are released. In other cases, the protease may be heat activated. In another example, the microcapsule comprises a shell wall comprising cellulose. The addition of the hydrolase chitosan serves as a biological trigger for the cleavage of the cellulose bonds, the depolymerization of the shell wall and the release of its internal contents.
C. Thermal stimulation
The microcapsules may also be induced to release their contents when a thermal stimulus is applied. Variations in temperature can cause multiple variations in the microcapsules. The change in heat may cause melting of the microcapsules, resulting in disintegration of the shell wall. In other cases, the heat may increase the internal pressure of the internal components of the capsule, causing the capsule to rupture or burst. In other cases, the heat may transform the capsules into a collapsed, dehydrated state. Heat may also act on the heat-sensitive polymer in the shell of the microcapsules to cause rupture of the microcapsules.
In one example, the microcapsules comprise a thermosensitive hydrogel shell encapsulating one or more emulsified reagent particles. Upon application of heat, e.g., above 35 ℃, the hydrogel material of the shell wall shrinks. The sudden contraction of the shell causes the capsule to rupture and the reagents inside the capsule to be sprayed into the sample preparation solution in the microwells.
In some cases, the shell wall may comprise a diblock polymer or a mixture of two polymers having different thermosensitivity. One polymer may be particularly likely to shrink upon application of heat, while the other is more thermally stable. When heat is applied to such a shell wall, the heat sensitive polymer may shrink while the other remains intact, causing the formation of pores. In other cases, the shell wall may comprise magnetic nanoparticles. Exposure to the magnetic field may result in the generation of heat, resulting in the rupture of the microcapsules.
D. Magnetic stimulation
The inclusion of magnetic nanoparticles in the shell wall of the microcapsules may allow triggered rupture of the capsules as well as directing the particles in the array. The device of the present disclosure may contain magnetic particles for either purpose. In one example, Fe3O4The nanoparticles are introduced into a polyelectrolyte-containing capsule and triggered to rupture in the presence of an oscillating magnetic field stimulus.
E. Electrical and optical stimulation
The microcapsules may also be broken or degraded by electrical stimulation. Like the magnetic particles described in the previous section, the electrically susceptible particles may allow triggered rupture of the capsule as well as other functions such as alignment in an electric field, electrical conductivity, or redox reactions. In one example, microcapsules containing electrically susceptible materials are aligned in an electric field so that the release of internal agents can be controlled. In other examples, the electric field may induce a redox reaction within the shell wall itself, which may increase porosity.
Light stimulation may also be used to rupture the microcapsules. Many optical triggers are possible and may include systems using a variety of molecules such as nanoparticles and chromophores capable of absorbing photons of a particular range of wavelengths. For example, a metal oxide coating may be used as a capsule trigger. To the SiO coated2/TiO2Ultraviolet irradiation of the polyelectrolyte capsules of (a) can result in disintegration of the capsule wall. In yet another example, photo-switchable materials, such as azobenzene groups, may be incorporated in the shell wall. Chemical substances such as these undergo upon photon absorption upon application of ultraviolet or visible lightReversible cis-to trans-isomerization. In this regard, the introduction of optical switches forms shell walls that can disintegrate or become more porous upon application of a light trigger.
F. Application of stimulation
The apparatus of the present disclosure may be used in combination with any device or apparatus that provides such triggering or stimulation. For example, if the stimulus is a thermal stimulus, the device may be used in combination with a heated or thermally controlled plate, which allows for heating of the microwells and may induce rupture of the capsules. Any of a number of heat transfers may be used for the thermal stimulus, including but not limited to applying heat by radiative, convective, or conductive heat transfer. In other cases, if the stimulus is a biological enzyme, the enzyme may be injected into the device such that it is deposited into individual microwells. On the other hand, if the stimulus is a magnetic or electric field, the device may be used in combination with a magnetic or electric plate.
The chemical stimulus may be added to the partition and may exert its function at different times after the chemical stimulus is contacted with the microcapsules. The rate at which the chemical stimulus exerts its effect may vary depending on, for example, the amount/concentration of chemical stimulus in contact with the microcapsule and/or the particular chemical stimulus used. For example, the microdroplets may comprise degradable gel beads (e.g., gel beads comprising chemical cross-linkers such as disulfide bonds). Upon droplet formation, a chemical stimulus (e.g., a reducing agent) may be included in the droplet with the gel beads. The chemical stimulus may degrade the gel bead immediately upon contact with the gel bead, shortly after contact with the gel bead (e.g., about 0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10min), or at a later time. In some cases, degradation of the gel beads may occur before, during, or after further processing steps, such as the thermal cycling steps described herein.
Sample preparation, reaction and recovery
After application of the stimulus, capsule rupture and reagent release, the sample preparation reaction can be performed in the device. The reaction within the device may be incubated for different periods of time depending on the reagents used in the sample reaction. The device may also be used in combination with other devices that assist in sample preparation reactions. For example, if PCR amplification is desired, the device may be used in combination with a PCR thermal cycler. In some cases, the thermal cycler can include a plurality of wells. In the case of a partition into droplets, the droplets may enter the wells of a thermal cycler. In some cases, each well may contain multiple droplets, such that when thermal cycling is initiated, multiple droplets are thermally cycled in each well. In another example, if the reaction requires agitation, the apparatus may be used in combination with a shaking device.
After the sample preparation reaction is completed, the analytes and products of the sample reaction can be recovered. In some cases, the device may employ a method that includes applying a liquid or gas to flush out the contents of a single microwell. In one example, the liquid comprises an immiscible carrier fluid that preferentially wets the microwell array material. It may also be immiscible with water to flush the reaction product out of the pores. In another example, the liquid may be an aqueous fluid that may be used to flush the sample out of the well. After rinsing the contents of the microwells, the contents of the microwells are combined for a variety of downstream analyses and applications.
Application of
FIG. 4A provides a general flow of various methods of the present disclosure; fig. 4B provides a generalized annotated version of 4A. One or more microcapsules containing reagents 410 may be preloaded into the microwells prior to addition of an analyte, which in this particular figure is a nucleic acid analyte 420. The microwells can then be sealed 430 by any method, such as by applying a sealing fluid. The inlet and outlet ports may also be sealed, for example, to prevent evaporation. Following these steps, a stimulus (e.g., heat, chemical, biological, etc.) may be applied to the micropores to rupture the microcapsules 460 and trigger the release of the agent 450 into the interior of the micropores. Subsequently, an incubation step 440 may occur to enable the reagent to perform a specific function, such as lysis of cells, digestion of proteins, fragmentation of high molecular weight nucleic acids, or ligation of oligonucleotide barcodes. Following the incubation step (which is optional), the contents of the microwells can be recovered individually or in bulk.
A. Analyte
The devices of the present disclosure may be widely applied to the manipulation, preparation, identification and/or quantification of analytes. In some cases, the analyte is a cell or a population of cells. The cell population can be homogeneous (e.g., cell lines from the same cell type, from the same type of tissue, from the same organ, etc.) or heterogeneous (a mixture of different types of cells). The cell may be a primary cell, a cell line, a recombinant cell, a primary cell, an encapsulated cell, an episomal cell, and the like.
The analyte may also be a molecule, including but not limited to: polypeptides, proteins, antibodies, enzymes, nucleic acids, carbohydrates, small molecules, drugs, and the like. Examples of nucleic acids include, but are not limited to: DNA, RNA, dNTP, ddNTP, amplicon, synthetic nucleotide, synthetic polynucleotide, oligonucleotide, peptide nucleic acid, cDNA, dsDNA, ssDNA, plasmid DNA, cosmid DNA, high Molecular Weight (MW) DNA, chromosomal DNA, genomic DNA, viral DNA, bacterial DNA, mtDNA (mitochondrial DNA), mRNA, rRNA, tRNA, nRNA, siRNA, snRNA, snoRNA, scaRNA, microRNA, dsRNA, ribozyme, riboswitch, and viral RNA (e.g., retroviral RNA).
In some cases, the analyte is pre-mixed with one or more additional materials, such as one or more reagents (e.g., ligase, protease, polymerase) prior to loading into the device. In some cases, the analyte is premixed with the microcapsules containing one or more reagents prior to loading onto the device.
The sample may be derived from a variety of sources, including human, mammalian, non-human mammalian, simian, monkey, chimpanzee, plant, reptile, amphibian, avian, fungal, viral or bacterial sources. Samples such as cells, nucleic acids and proteins may also be obtained from a variety of clinical sources such as biopsies, aspirates, blood draws, urine samples, formalin-fixed embedded tissues, and the like.
The devices of the present disclosure may also enable analytes to be labeled or tracked to allow for subsequent identification of the source of the analyte. This feature is in contrast to other methods that use pooled or multiplexed reactions and provide only measurements or analyses as an average of multiple samples. Here, the physical segmentation and assignment of unique identifiers to individual analytes allows data to be acquired from individual samples and is not limited to the average of the samples.
In some examples, nucleic acids or other molecules derived from a single cell may share a common tag or identifier and thus may be later identified as being derived from that cell. Similarly, all fragments from one strand of a nucleic acid may be labeled with the same identifier or tag, thereby allowing subsequent identification of fragments with similar phasing or ligation on the same strand. In other cases, gene expression products (e.g., mRNA, protein) from a single cell can be labeled to quantify expression. In other cases, the device can be used as a PCR amplification control. In such cases, multiple amplification products from a PCR reaction may be labeled with the same tag or identifier. If the products are subsequently sequenced and sequence differences are demonstrated, differences between products with the same identifier can be attributed to PCR errors.
The analyte may be loaded onto the device before, after, or during the loading of the microcapsules and/or free reagents. In some cases, the analyte is encapsulated within the microcapsules prior to loading into the microcapsule array. For example, the nucleic acid analyte may be encapsulated into microcapsules, which are then loaded onto the device and later triggered to release the analyte into the appropriate microwells.
Any analyte, such as DNA or cells, may be loaded in solution or as an analyte encapsulated in a capsule. In some cases, a homogeneous or heterogeneous population of molecules (e.g., nucleic acids, proteins, etc.) is encapsulated into microcapsules and loaded onto a device. In some cases, a homogeneous or heterogeneous population of cells is encapsulated into microcapsules and loaded onto a device. The microcapsules may contain a random or specific number of cells and/or molecules. For example, the microcapsule may comprise no more than 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 500, 1000, 5000, or 10000 cells and/or molecules per microcapsule. In other examples, the microcapsule comprises at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 500, 1000, 5000, or 10000 cells and/or molecules/microcapsule. Fluidic techniques and any other technique may be used to encapsulate cells and/or molecules into microcapsules.
In general, the methods and compositions provided herein can be used to prepare analytes prior to downstream applications such as sequencing reactions. Typically, the sequencing method is classical Sanger sequencing. Sequencing methods may include, but are not limited to: high throughput sequencing, pyrosequencing, sequencing-by-synthesis, single molecule sequencing, nanopore sequencing, ligation sequencing, sequencing-by-hybridization, RNA sequencing (Illumina), digital gene expression (Helicos), next generation sequencing, single molecule sequencing-by-synthesis (SMSS) (Helicos), massively parallel sequencing, clonal single molecule arrays (Solexa), shotgun sequencing, Maxim-Gilbert sequencing, primer walking, and any other sequencing method known in the art.
There are many examples of applications that can be performed in place of or in conjunction with sequencing reactions, including but not limited to: biochemical analysis, proteomics, immunoassays, profiling/fingerprinting of specific cell types, drug screening, bait-capture experiments, protein-protein interaction screening, etc.
B. Assignment of unique identifiers to analytes
The devices disclosed herein may be used in applications involving the assignment of unique identifiers or molecular barcodes to analytes. Typically, the unique identifier is a barcode oligonucleotide used to label the analyte; however, in some cases, a different unique identifier is used. For example, in some cases, the unique identifier is an antibody, in which case the attachment can include a binding reaction between the antibody and the analyte (e.g., antibody and cell, antibody and protein, antibody and nucleic acid). In other cases, the unique identifier is a dye, in which case attachment may include intercalation of the dye into the analyte molecule (e.g., into DNA or RNA) or binding to a dye-labeled probe. In other cases, the unique identifier can be a nucleic acid probe, in which case, attaching to the analyte can include a hybridization reaction between the nucleic acid and the analyte. In some cases, the reaction may include a chemical linkage between the identifier and the analyte. In other cases, the reaction may include the addition of the metal isotope directly to the analyte or through a probe labeled with the isotope.
Typically, the method comprises attaching an oligonucleotide barcode to a nucleic acid analyte by an enzymatic reaction, such as a ligation reaction. For example, a ligase can covalently attach a DNA barcode to fragmented DNA (e.g., high molecular weight DNA). After barcode attachment, the molecule can be subjected to a sequencing reaction.
However, other reactions may also be used. For example, oligonucleotide primers comprising a barcode sequence can be used in an amplification reaction (e.g., PCR, qPCR, reverse transcriptase PCR, digital PCR, etc.) of a DNA template analyte, thereby producing a labeled analyte. After the barcode is dispensed to a single analyte, the contents of the single microwell can be recovered via an outlet port in the device for further analysis.
Unique identifiers (e.g., oligonucleotide barcodes, antibodies, probes, etc.) can be introduced to the device randomly or non-randomly. In some cases, they are introduced in the desired ratio between the unique identifier and the microwell. For example, the unique identifiers can be loaded such that each microwell is loaded with more than about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 50, 100, 500, 1000, 5000, 10000, or 200000 unique identifiers. In some cases, the unique identifiers can be loaded such that each microwell is loaded with less than about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 50, 100, 500, 1000, 5000, 10000, or 200000 unique identifiers. In some cases, the average number of unique identifiers loaded per microwell is less than or greater than about 0.0001, 0.001, 0.01, 0.1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 50, 100, 500, 1000, 5000, 10000, or 200000 unique identifiers per microwell.
Unique identifiers may also be loaded so that a set of one or more identical identifiers is introduced into a particular well. Such sets may also be loaded such that each microwell contains an identifier of a different set. For example, a population of microcapsules can be prepared such that a first microcapsule in the population comprises multiple copies of the same unique identifier (e.g., a nucleic acid barcode, etc.) and a second microcapsule in the population comprises multiple copies of a different unique identifier than in the first microcapsule. In some cases, a population of microcapsules may comprise a plurality of microcapsules (e.g., more than 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 100, 500, 1000, 5000, 10000, 100000, 1000000, 10000000, 100000000, or 1000000000 microcapsules), each comprising multiple copies of a distinct unique identifier that is contained in other microcapsules. In some cases, the population may comprise more than 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 100, 500, 1000, 5000, 10000, 100000, 1000000, 10000000, 100000000, or 1000000000 microcapsules having the same set of unique identifiers. In some cases, the population may comprise more than 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 100, 500, 1000, 5000, 10000, 100000, 1000000, 10000000, 100000000, or 1000000000 microcapsules, wherein the microcapsules each comprise a different combination of unique identifiers. For example, in some cases, different combinations overlap such that a first microcapsule can include unique identifiers A, B and C, for example, while a second microcapsule can include unique identifiers A, B and D. In another example, the different combinations do not overlap such that the first microcapsule can include unique identifiers A, B and C, for example, and the second microcapsule can include unique identifiers D, E and F.
The unique identifier can be loaded into the device at an expected or predicted unique identifier/analyte (e.g., nucleic acid strand, nucleic acid fragment, protein, cell, etc.) ratio. In some cases, the unique identifiers are loaded into the microwells such that each individual analyte in the microwells is loaded with more than about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 50, 100, 500, 1000, 5000, 10000, or 200000 unique identifiers. In some cases, the unique identifiers are loaded into the microwells such that each individual analyte in the microwell is loaded with less than about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 50, 100, 500, 1000, 5000, 10000, or 200000 unique identifiers. In some cases, the average number of unique identifiers loaded per analyte is less than or greater than about 0.0001, 0.001, 0.01, 0.1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 50, 100, 500, 1000, 5000, 10000, or 200000 unique identifiers per analyte. When more than one identifier is present per analyte, such identifiers may be copies of the same identifier or multiple different identifiers. For example, the attachment process may be designed to attach multiple identical identifiers to a single analyte, or multiple different identifiers to an analyte.
The unique identifier can be used to label a wide variety of analytes, including cells or molecules. For example, a unique identifier (e.g., a barcode oligonucleotide) can be attached to the entire strand of a nucleic acid or to a fragment of a nucleic acid (e.g., fragmented genomic DNA, fragmented RNA). The unique identifier (e.g., antibody, oligonucleotide) can also bind to a cell, including the outer surface of the cell, a marker expressed on the cell, or a component within the cell, such as an organelle, a gene expression product, genomic DNA, mitochondrial DNA, RNA, mRNA, or a protein. The unique identifier may also be designed to bind to or hybridize to nucleic acids (e.g., DNA, RNA) present in permeabilized cells, which may or may not otherwise be intact.
The unique identifier may be loaded onto the device alone or in combination with other elements (e.g., reagents, analytes). In some cases, the free unique identifier is combined with the analyte and the mixture is loaded into the device. In some cases, the unique identifier encapsulated in the microcapsule is combined with the analyte prior to loading the mixture onto the device. In other cases, the free unique identifier is loaded into the microwell before, during (e.g., through a separate inlet port), or after the analyte is loaded. In other cases, the unique identifier encapsulated in the microcapsule is loaded into the microwell before, simultaneously with (e.g., through a separate inlet port), or after the analyte is loaded.
In many applications, it may be important to determine whether individual analytes each receive a different unique identifier (e.g., an oligonucleotide barcode). If the population of unique identifiers introduced into the device is not significantly diverse, different analytes may be labeled with the same identifier. The devices disclosed herein may enable detection of analytes labeled with the same identifier. In some cases, a reference analyte may be included with the population of analytes introduced into the device. The reference analyte can be, for example, a nucleic acid having a known sequence and a known amount. After the population of analytes is loaded into the device and partitioned in the device, the unique identifier can be attached to the analytes as described herein. If the unique identifier is an oligonucleotide barcode and the analyte is a nucleic acid, the labeled analyte can then be sequenced and quantified. These methods may indicate whether one or more fragments and/or analytes may have been assigned the same barcode.
The methods disclosed herein may include loading into the device the reagents necessary for dispensing the barcode to the analyte. In the case of a ligation reaction, reagents including, but not limited to, ligase, buffer, adaptor oligonucleotides, multiple unique identifier DNA barcodes, and the like may be loaded into the device. In the case of enrichment, reagents including, but not limited to, a plurality of PCR primers, oligonucleotides comprising unique identification sequences or barcode sequences, DNA polymerase, DNTPs, and buffers, etc. may be loaded into the device. The reagent may be loaded as a free reagent or as a reagent encapsulated in a microcapsule.
C. Nucleic acid sequencing
Nucleic acid sequencing can begin by physically partitioning sample analytes into microwells at a particular density (e.g., about 1 analyte per microwell or other densities described herein). When assigning nucleic acid barcodes to individual analytes, it is then possible to track individual molecules during subsequent steps, such as subsequent amplification and/or sequencing steps, even if the analytes are later brought together and processed together.
a. Nucleic acid phasing
The devices provided herein can be used to prepare analytes (e.g., nucleic acid analytes) in a manner that enables phasing or ligation information to be subsequently obtained. Such information may allow detection of linked genetic variations in a sequence, including genetic variations separated by long nucleic acid segments (e.g., SNPs, mutations, indels, copy number variations, transversions, translocations, inversions, etc.). These variations may exist in cis or trans relationships. In a cis relationship, two or more genetic variations may be present in the same polynucleic acid molecule or strand. In a trans relationship, two or more genetic variations may be present on multiple nucleic acid molecules or strands.
Methods of determining nucleic acid phasing can include: loading a nucleic acid sample (e.g., a nucleic acid sample spanning one or more given loci) into a device disclosed herein, dispensing the sample such that no more than one molecule of nucleic acid is present in each microwell, and fragmenting the sample in the microwells. The method may further comprise: attaching a unique identifier (e.g., a barcode) to the fragmented nucleic acids described herein, recovering the nucleic acids in bulk, and performing subsequent sequencing reactions on the sample to detect genetic variations, e.g., two different genetic variations. Detection of genetic variation tagged with two different barcodes may indicate that the two genetic variations originate from two separate strands of DNA, reflecting a trans-relationship. Conversely, detection of two different genetic variations labeled with the same barcode may indicate that the two genetic variations are from the same strand of DNA, reflecting a cis relationship.
Information is believed to be critical to the characterization of the analyte, particularly when the analyte originates from a subject having or suspected of having a particular disease or disorder (e.g., an inherited recessive disease, such as cystic fibrosis, cancer, etc.) or at risk thereof. This information may be able to distinguish between the following possibilities: (1) two genetic variations are located within the same gene on the same strand of DNA, and (2) two genetic variations are located within the same gene but on separate strands of DNA. Likelihood (1) may indicate that a copy of the gene is normal and that the individual is free of the disease, while likelihood (2) may indicate that the individual has or will develop the disease, particularly when the two genetic variations impair gene function when present within the same gene copy. Similarly, it is also possible to distinguish the following possibilities: (1) two genetic variations, each located in a different gene on the same strand of DNA, and (2) two genetic variations, each located in a different gene but on a separate strand of DNA.
b. Cell-specific information
The devices provided herein can be used to prepare cellular analytes in a manner that enables cell-specific information to be subsequently obtained. Such information may allow for detection of genetic variation (e.g., SNPs, mutations, indels, copy number variations, transversions, translocations, inversions, etc.) on a cell-by-cell basis, thereby enabling determination of whether the genetic variation is present in the same cell or in two different cells.
Methods of determining nucleic acid cell-specific information can include: loading a cell sample (e.g., a cell sample from a subject) into the device disclosed herein, partitioning the sample so that no more than one cell is present per microwell, lysing the cells, and then labeling nucleic acids within the cells with a unique identifier using the methods described herein. In some cases, microcapsules containing a unique identifier are loaded into a microwell array device (before, during, or after cellular analyte loading) in such a way that each cell is in contact with a different microcapsule. The resulting labeled nucleic acids can then be pooled, sequenced, and used to track the source of the nucleic acids. It can be determined that nucleic acids having the same unique identifier originate from the same cell, while nucleic acids having different unique identifiers originate from different cells.
In a more specific example, the methods herein can be used to detect the distribution of oncogenic mutations throughout a population of cancer tumor cells. In this example, some cells may have a mutation or amplification (homozygous) of an oncogene (e.g., HER2, BRAF, EGFR, KRAS) on both strands of DNA, while other cells may be heterozygous for the mutation, while still some cells may be wild-type and contain no mutations or other variations in the oncogene. The methods described herein may be capable of detecting these differences, and may also enable quantification of the relative numbers of homozygous, heterozygous, and wild-type cells. Such information can be used to stage a particular cancer or to monitor the progression of a cancer over time.
In some examples, the disclosure provides methods of identifying mutations in two different oncogenes (e.g., KRAS and EGFR). If the same cell contains a gene with two mutations, this may indicate a more aggressive form of cancer. In contrast, if the mutation is located in two different cells, this may indicate that the cancer is more benign or less advanced.
Another specific example of cell-specific sequence determination is as follows. In this example, a plurality of cells (such as from a tumor biopsy) are loaded into the device. Individual cells from the sample are deposited into individual wells and labeled with DNA barcodes.
The loading of cells into the device may be achieved by non-random loading. The parameters for the non-random loading of analytes, such as cells, can be understood using the following interference functions, such that:wherein the content of the first and second substances,
probability that a particular cell will try but not fit into a well (measure of interference)
N is the number of holes
L-mark-number of bar codes
C-the number of cells.
As part of the sample preparation reaction, the cells may be lysed and a number of subsequent reactions may be performed, including RNA amplification, DNA amplification, or antibody screening against different target proteins and genes in individual cells. After the reaction, the contents of the cells can be pooled together and can be further analyzed, for example by DNA sequencing. Since each cell is assigned a unique barcode, further analysis is possible, including but not limited to quantification of different gene levels or nucleic acid sequencing of individual cells. In this example, it can be determined whether a tumor contains cells with different genetic backgrounds (e.g., cancer clones and subclones). The relative number of each cell type can also be calculated.
c. Amplification control
As disclosed herein, the device can be used for the purpose of controlling amplification errors, such as PCR errors. For example, a nucleic acid sample can be dispensed into a microwell of the device. After dispensing, the sample may undergo a PCR amplification reaction within the microwells. Using the methods described herein, PCR products within a microwell can be labeled with the same unique identifier. If the products are later sequenced and show sequence differences, differences between products with the same identifier can be attributed to PCR errors.
d. Analysis of Gene expression products
In other applications, the device may be used to detect (typically cell-by-cell) the level of expression of a gene product (e.g., protein, mRNA) in a sample. The sample may comprise a single cell, a pool of mRNA extracts extracted from cells, or other collection of gene products. In some cases, a single cell may be loaded into a microwell. In other cases, a pool of mRNA or other gene products can be loaded such that a desired amount of mRNA molecules are loaded into a single microwell.
The methods provided herein may be particularly useful for RNA analysis. For example, using the methods provided herein, a unique identifier can be assigned directly to an mRNA analyte or to a cDNA product of a reverse transcription reaction performed on an mRNA analyte. After the analyte is loaded, a reverse transcription reaction may be performed within the microwells of the device. Reagents for this reaction may include, but are not limited to, reverse transcriptase, DNA polymerase, buffers, dntps, oligonucleotide primers containing barcode sequences, and the like. One or more reagents may be loaded into the microcapsules or loaded into the device free in solution, or a combination thereof. Sample preparation can then be performed, for example, by fragmenting the cDNA and attaching a unique identifier to the fragment. After sample preparation and recovery, the nucleic acid products of the reaction can be further analyzed, for example, by sequencing.
Furthermore, similar to flow cytometry, the device can be used to characterize a plurality of cellular markers. Any cellular marker can be characterized, including cell surface markers (e.g., extracellular proteins, transmembrane markers) and markers located inside the cell (e.g., RNA, mRNA, microRNA, multiple copies of a gene, proteins, alternative splice products, etc.). For example, as described herein, cells may be partitioned within the device such that at most one cell is present within a microwell. Cellular markers such as nucleic acids (e.g., RNA) can be extracted and/or fragmented prior to labeling with a unique identifier (e.g., a molecular barcode). Alternatively, the nucleic acid may be tagged with a unique identifier without extraction or fragmentation. The nucleic acid may then undergo further analysis, such as a sequencing reaction designed to detect the expression products of various genes. Such analysis can be used in a number of fields. For example, if the starting cell is an immune cell (e.g., T cell, B cell, macrophage, etc.), the assay may provide information about multiple expressed markers and enable immunophenotypic analysis of the cell, e.g., by identifying different CD markers (e.g., CD3, CD4, CD8, CD19, CD20, CD56, etc.) of the cell. Such markers may provide insight into the function, nature, class or relative maturity of the cell. Such markers may also be used in combination with markers that are not necessarily immunophenotypic assay markers, such as markers of pathogenic infection (e.g., viral or bacterial proteins, DNA, or RNA). In some cases, the device can be used to identify at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 200, 500, 700, 1000, 5000, 10000, 50000, or 100000 different gene expression products or other forms of cellular markers on a single cell basis. Typically, such methods do not involve the use of dyes or probes (e.g., fluorescent probes or dyes).
Gene expression product analysis can be used in many fields, including immunology, cancer biology (e.g., to characterize the presence, type, stage, aggressiveness, or other characteristics of cancer tissue), stem cell biology (e.g., to characterize the differentiation state of stem cells, the potency of stem cells, the cell type of stem cells, or other characteristics of stem cells), microbiology, and the like. Gene expression analysis can also be used in drug screening applications, for example to assess the effect of a particular drug or agent on the gene expression profile of a particular cell.
Term of
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the devices of the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Furthermore, to the extent that the terms "includes," including, "" has, "" with, "or variants thereof are used in either the detailed description and/or the claims, such terms are intended to be inclusive in a manner similar to the term" comprising.
Aspects of the apparatus of the present disclosure are described above with reference to example applications for illustration. It should be understood that numerous specific details, relationships, and methods are set forth to provide a full understanding of the apparatus. However, one of ordinary skill in the relevant art will readily recognize that: the apparatus may be practiced without one or more of these specific details or with other methods. The present disclosure is not limited by the illustrated ordering of acts or events, as some acts may occur in different orders and/or concurrently with other acts or events. Moreover, not all illustrated acts or events are required to implement a methodology in accordance with the present disclosure.
Ranges may be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. The term "about" as used herein refers to a range of specified values ± 15% in the context of a particular application. For example, about 10 would include a range from 8.5 to 11.5.
The term microwell array as used herein generally refers to a predetermined spatial arrangement of microwells. The microwell array device containing microcapsules may also be referred to as a "microwell capsule array". Further, the term "array" may be used herein to refer to multiple arrays arranged on a surface, such as where the surface has multiple copies of an array. Such a surface carrying multiple arrays may also be referred to as a "multiple array" or a "repeating array".
The present invention provides embodiments including, but not limited to:
1. a composition comprising a first microcapsule, wherein:
a. the microcapsules are degradable when a stimulus is applied to the first microcapsules; and is
b. The first microcapsule comprises an oligonucleotide barcode.
2. The composition of embodiment 1, wherein the first microcapsule comprises a chemical cross-linker.
3. The composition of embodiment 2, wherein the chemical cross-linker is a disulfide bond.
4. The composition of embodiment 1, further comprising a polymer gel.
5. The composition of embodiment 4, wherein the polymer gel is a polyacrylamide gel.
6. The composition of embodiment 1, wherein the first microcapsule comprises a bead.
7. The composition of embodiment 6, wherein the bead is a gel bead.
8. The composition of embodiment 1, wherein the stimulus is selected from the group consisting of a biological stimulus, a chemical stimulus, a thermal stimulus, an electrical stimulus, a magnetic stimulus, or a light stimulus, and combinations thereof.
9. The composition of embodiment 1, wherein the chemical stimulus is selected from the group consisting of a change in pH, a change in ionic concentration, and a reducing agent.
10. The composition of embodiment 9, wherein the reducing agent is Dithiothreitol (DTT) or tris (2-carboxyethyl) phosphine (TCEP).
11. The composition of embodiment 1, wherein a second microcapsule comprises said first microcapsule.
12. The composition of embodiment 11, wherein said second microcapsule is a droplet.
13. The composition of embodiment 1, further comprising a nucleic acid comprising the oligonucleotide barcode, wherein the nucleic acid comprises a deoxyuridine triphosphate (dUTP).
14. The composition of embodiment 1, further comprising a polymerase incapable of accepting deoxyuridine triphosphate (dUTP).
15. The composition of embodiment 1, further comprising a target analyte.
16. The composition of embodiment 15, wherein said target analyte is a nucleic acid.
17. The composition of embodiment 16, wherein said nucleic acid is selected from the group consisting of DNA, RNA, dNTP, ddNTP, amplicon, synthetic nucleotide, synthetic polynucleotide, oligonucleotide, peptide nucleic acid, cDNA, dsDNA, ssDNA, plasmid DNA, cosmid DNA, high Molecular Weight (MW) DNA, chromosomal DNA, genomic DNA, viral DNA, bacterial DNA, mtDNA (mitochondrial DNA), mRNA, rRNA, tRNA, nRNA, siRNA, snRNA, snoRNA, scaRNA, microRNA, dsRNA, ribozyme, riboswitch, and viral RNA.
18. The composition of embodiment 16, wherein the nucleic acid is genomic dna (gdna).
19. The composition of embodiment 1, wherein the density of oligonucleotide barcodes is at least about 1,000,000 oligonucleotide barcodes per said first microcapsule.
20. The composition of embodiment 1, wherein the oligonucleotide barcode is coupled to the microcapsule by a chemical cross-linker.
21. The composition of embodiment 20, wherein the chemical cross-linker is a disulfide bond.
22. An apparatus comprising a plurality of partitions, wherein:
a. at least one partition of the plurality of partitions comprises microcapsules containing oligonucleotide barcodes; and is
b. The microcapsules are degradable when a stimulus is applied to the microcapsules.
23. The device of embodiment 22, wherein said partition is a well.
24. The device of embodiment 22, wherein the partitions are droplets.
25. The device of embodiment 22, wherein the microcapsules comprise a chemical cross-linker.
26. The device of embodiment 25, wherein said chemical cross-linker is a disulfide bond.
27. The device of embodiment 22, wherein said microcapsules further comprise a polymeric gel.
28. The device of embodiment 27, wherein said polymer gel is a polyacrylamide gel.
29. The device of embodiment 22, wherein the microcapsules comprise beads.
30. The device of embodiment 29, wherein said beads are gel beads.
31. The device of embodiment 22, wherein the stimulus is selected from the group consisting of a biological stimulus, a chemical stimulus, a thermal stimulus, an electrical stimulus, a magnetic stimulus, or a light stimulus, and combinations thereof.
32. The device of embodiment 31, wherein the chemical stimulus is selected from the group consisting of a change in pH, a change in ionic concentration, and a reducing agent.
33. The device of embodiment 32, wherein the reducing agent is Dithiothreitol (DTT) or tris (2-carboxyethyl) phosphine (TCEP).
34. The device of embodiment 22, wherein nucleic acids comprise the oligonucleotide barcodes, and wherein the nucleic acids comprise deoxyuridine triphosphate (dUTP).
35. The device of embodiment 22, wherein said partition comprises a polymerase incapable of accepting deoxyuridine triphosphate (dUTP).
36. The device of embodiment 22, wherein said partition comprises a target analyte.
37. The device of embodiment 36, wherein the target analyte is a nucleic acid.
38. The device of embodiment 37, wherein said nucleic acid is selected from the group consisting of DNA, RNA, dNTP, ddNTP, amplicon, synthetic nucleotide, synthetic polynucleotide, oligonucleotide, peptide nucleic acid, cDNA, dsDNA, ssDNA, plasmid DNA, cosmid DNA, high Molecular Weight (MW) DNA, chromosomal DNA, genomic DNA, viral DNA, bacterial DNA, mtDNA (mitochondrial DNA), mRNA, rRNA, tRNA, nRNA, siRNA, snRNA, snoRNA, scaRNA, microRNA, dsRNA, ribozyme, riboswitch, and viral RNA.
39. The device of embodiment 37, wherein the nucleic acid is genomic dna (gdna).
40. The device of embodiment 22, wherein the oligonucleotide barcodes are coupled to the microcapsules by chemical cross-linkers.
41. The device of embodiment 40, wherein the chemical cross-linker is a disulfide bond.
42. A method for sample preparation, the method comprising:
a. incorporating into a partition a microcapsule comprising an oligonucleotide barcode and a target analyte, wherein the microcapsule is degradable upon application of a stimulus to the microcapsule; and
b. applying the stimulus to the microcapsules to release the oligonucleotide barcodes to the target analyte.
43. The method of embodiment 42, wherein the partitions are wells.
44. The method of embodiment 42, wherein the partitions are microdroplets.
45. The method of embodiment 42, wherein the microcapsule comprises a polymer gel.
46. The method of embodiment 45, wherein the polymer gel is polyacrylamide.
47. The method of embodiment 42, wherein the microcapsule comprises a bead.
48. The method of embodiment 47, wherein said beads are gel beads.
49. The method of embodiment 42, wherein the microcapsule comprises a chemical cross-linker.
50. The method of embodiment 49, wherein the chemical cross-linker is a disulfide bond.
51. The method of embodiment 42, wherein said stimulation is selected from the group consisting of biological, chemical, thermal, electrical, magnetic or optical stimulation and combinations thereof.
52. The method of embodiment 51, wherein the chemical stimulus is selected from the group consisting of a change in pH, a change in ionic concentration, and a reducing agent.
53. The method of embodiment 52, wherein the reducing agent is Dithiothreitol (DTT) or tris (2-carboxyethyl) phosphine (TCEP).
54. The method of embodiment 42, wherein nucleic acid comprises the oligonucleotide barcode, and wherein the nucleic acid comprises deoxyuridine triphosphate (dUTP).
55. The method of embodiment 42, wherein said partition comprises a polymerase incapable of accepting deoxyuridine triphosphate (dUTP).
56. The method of embodiment 42, further comprising attaching said oligonucleotide barcode to said target analyte.
57. The method of embodiment 56, wherein said attaching is accomplished using a nucleic acid amplification reaction.
58. The method of embodiment 42, wherein said target analyte is a nucleic acid.
59. The method of embodiment 58, wherein the nucleic acid is selected from the group consisting of DNA, RNA, dNTP, ddNTP, amplicon, synthetic nucleotide, synthetic polynucleotide, oligonucleotide, peptide nucleic acid, cDNA, dsDNA, ssDNA, plasmid DNA, cosmid DNA, high Molecular Weight (MW) DNA, chromosomal DNA, genomic DNA, viral DNA, bacterial DNA, mtDNA (mitochondrial DNA), mRNA, rRNA, tRNA, nRNA, siRNA, snRNA, snoRNA, scaRNA, microRNA, dsRNA, ribozyme, riboswitch, and viral RNA.
60. The method of embodiment 58, wherein the nucleic acid is genomic DNA (gDNA).
61. The method of embodiment 42, wherein the oligonucleotide barcodes are coupled to the microcapsules by chemical cross-linkers.
62. The method of embodiment 61, wherein the chemical cross-linker is a disulfide bond.
63. A composition comprising degradable gel beads, wherein the degradable gel beads comprise at least about 1,000,000 oligonucleotide barcodes.
64. The composition of embodiment 63, wherein the 1,000,000 oligonucleotide barcodes are identical.
Example 1 Single cell DNA sequencing
A microwell capsule array was prepared to perform nucleic acid sequencing on individual human B cells obtained from a blood sample. Approximately 15,000 cells were harvested and used to load into the device. A device of the present disclosure and containing 150,000 microwells was used. The individual wells were cylindrical in shape with a diameter of 125 μm and a height of 125 μm, which allowed loading up to 1 capsule per well. Microcapsules with PNIPAM hydrogel shell walls made by emulsion polymerization were produced such that the microcapsules had a diameter of 100 μm for loading into the device. The microcapsules are produced such that the PNIPAM shell contains magnetic iron particles. The outer surface of the shell is then chemically coupled to antibodies specific for transmembrane B cell receptors on the exterior of the B cell.
During the preparation of the capsules, the reagents are loaded into the capsules simultaneously. The capsules are loaded with the reagents necessary for cell lysis and labeling of the individual DNA strands of the cells with DNA barcodes. Reagents for cell lysis include mild non-ionic detergents, buffers and salts. The capsules were loaded with reagents for the addition of DNA barcodes to genomic DNA, including restriction enzymes, ligase, and >10,000,000 unique DNA oligonucleotides. The capsules are designed to be sensitive to rupture above 65 ℃.
Capsules are prepared for application to an array of microcapsules. The array is placed on a magnetic temperature controlled hot plate. Microcapsules are added to a sample of B cells so that one B cell can bind to one capsule. The capsule-cell conjugate is applied in an aqueous carrier solution in an amount that exceeds the relative number of pores. The capsule-cells were gently pipetted into the inlet port, followed by application of a vacuum manifold to the outlet port to dispense the capsule throughout the device. A magnetic field is applied through the plate. Excess capsule-cell solution was removed via pipetting through the outlet port. Individual capsule-cell conjugates were captured by magnetic field and positioned in individual wells.
After loading the cells and capsules into the device, a carrier oil (or sealing fluid) is applied to the device to remove any excess aqueous solution bridging adjacent microwells. Carrier oil is applied to the inlet and excess oil is recovered at the outlet with a vacuum manifold. After the carrier oil is applied, the inlet and outlet ports are sealed with tape.
The device was then heated to a temperature of 70 ℃ by a magneto-temperature controlled hot plate for 10 minutes to rupture the capsules and lyse the cells. The hotplate was then switched to 37 ℃ for restriction digestion and ligation, held for up to 1 hour.
After the sample preparation reaction was complete, the contents of the wells were recovered. The inlet and outlet ports of the device were unsealed and nitrogen was applied to the device to flush out the individual components of the micropores. Samples were collected in batches via pipette at the outlet port while the magnetic field retained the ruptured capsule shells in the individual microwells.
The sample is then sequenced using multiplex sequencing strategies known in the art. Barcode encoding of individual cells allows sequencing information to be obtained for individual cells, rather than as an average over multiple cells. SNP cell-specific information was obtained based on the number of sequenced cells and assigned barcodes. Furthermore, the number of reads of a single barcode can be counted to provide insight into the distribution of different cell types with different genetic backgrounds in the original population of B cells.
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