Electrochemical analysis method for determining activity of T4 polynucleotide kinase based on magnetic nano material
阅读说明：本技术 基于磁性纳米材料测定t4多聚核苷酸激酶活性的电化学分析方法 (Electrochemical analysis method for determining activity of T4 polynucleotide kinase based on magnetic nano material ) 是由 张艳丽 陶锦彭 庞鹏飞 王红斌 于 2020-12-08 设计创作，主要内容包括：本发明公开了一种基于磁性纳米材料测定T4多聚核苷酸激酶活性的电化学分析方法,包括如下步骤：采用水热法制备Fe-3O-4@TiO-2磁性核壳纳米粒子,ATP和T4 PNK存在时,核酸链S1的5′端磷酸化,末端磷酸化的S1通过与TiO-2特异性反应,修饰到Fe-3O-4@TiO2磁性纳米粒子表面；加入金纳米粒子-核酸链S-2复合物(AuNPs-S2),由于核酸链S1和S2之间的杂交反应,形成Fe-3O-4@TiO-2-S1/S2-AuNPs复合物；以六氨基合钌[Ru(NH-3)-6～(3+)]为电活性指示剂,通过GME表面的磁性富集和电化学信号增强,实现对T4PNK活性的高灵敏、快速和定量测定。(The invention discloses an electrochemical analysis method for determining T4 polynucleotide kinase activity based on a magnetic nano material, which comprises the following steps: preparation of Fe by hydrothermal method 3 O 4 @TiO 2 Magnetic core-shell nanoparticles, ATP and T4PNK, the 5' end of the nucleic acid chain S1 is phosphorylated, and the phosphorylated S1 at the end is reacted with TiO 2 Specific reaction, modification to Fe 3 O 4 @ TiO2 magnetic nanoparticle surface; addition of gold nanoparticle-nucleic acid strand S 2 Complex (AuNPs-S2) due to hybridization between nucleic acid strands S1 and S2React to form Fe 3 O 4 @TiO 2 -S1/S2-AuNPs complex; with hexa-amino ruthenium [ Ru (NH) 3 ) 6 3+ ]The GME is an electroactive indicator, and the high-sensitivity, rapid and quantitative determination of the T4PNK activity is realized through the magnetic enrichment and electrochemical signal enhancement of the GME surface.)
1. An electrochemical analysis method for determining the activity of T4 polynucleotide kinase based on magnetic nano materials is characterized by comprising the following steps: (1) designing an oligonucleotide sequence;
(2)Fe3O4magnetic nanoparticles;
(3)Fe3O4@TiO2magnetic core-shell nanoparticles:
(4)AuNPs-S2preparing nano particles;
(5) constructing an electrochemical biosensor:
adding ATP and T4PNK into nucleic acid chain S1 buffer solution, incubating at 37 deg.C for 4 hr, and adding Fe3O4@TiO2Magnetic core-shell nano particle solution culture methodBreeding for 4 hours; then adding AuNPs-S2Incubating the nanoparticle solution at 37 ℃ for 2-3 hours; then the mixed solution is dripped on the surface of the treated magnetic gold electrode GME, and [ Ru (NH) is dripped after the electrode is washed by PBS buffer solution3)6]3+An electroactive species that measures an electrochemical response signal of the electrode;
(6) the kinase activity of the T4 polynucleotide is measured, an electrochemical workstation is used for testing in a three-electrode system, differential pulse voltammetry DPV is adopted for quantification, and a standard curve of the relation between the DPV peak current and the T4PNK activity is drawn.
2. The electrochemical assay method for determining the kinase activity of T4 polynucleotide based on magnetic nanomaterial of claim 1, wherein: in step (1), the nucleic acid strand S1Has a nucleotide sequence shown as SEQ ID No. 1; the nucleic acid strand S2Has a nucleotide sequence shown as SEQ ID No. 2;
in the step (2), firstly, a hydrothermal method is adopted to prepare Fe3O4Magnetic nanoparticles of FeCl3Dissolving in ethylene glycol, adding NaAc and polyethylene glycol, stirring for dissolving, transferring to a polytetrafluoroethylene autoclave, reacting at 200 deg.C for 8 hr, cooling to room temperature, washing with ethanol for several times, magnetically separating, and drying at room temperature to obtain Fe3O4Magnetic nanoparticles;
in the step (3), glacial acetic acid and butyl titanate are dissolved in ethanol, and Fe is added3O4Adding polyethylene glycol and urea after ultrasonic dispersion of nano particles, stirring and dissolving, transferring the mixture into a reaction container, reacting for 8 hours at 180 ℃, filtering precipitates, washing the precipitates with ethanol for a plurality of times, and drying for 12 hours at 80 ℃ to obtain Fe3O4@TiO2Magnetic core-shell nanoparticles;
in step (4), preparation of AuNPs-S2 nanoparticles:
dissolving a nucleic acid chain S2 in a PBS buffer solution, adding an AuNPs solution, incubating for 4 hours at 37 ℃, adding a colloidal solution, standing for 4 hours, washing with the PBS buffer solution, and performing centrifugal separation to obtain AuNPs-S2 nanoparticles;
in the step (5), the step (c),
adding gold nano particle-nucleic acid chain S2 complex (AuNPs-S2), nucleic acid chain S1And S2Through specific hybridization reaction, AuNPs are modified to Fe3O4@TiO2Fe is formed on the surface of the magnetic nanoparticles3O4@TiO2-S1/S2-AuNPs complex;
in step (6), the working electrode is used as hexaaminoruthenium Ru (NH)3)6 3+The T4PNK activity is an electroactive indicator, and the quantitative determination of the T4PNK activity is realized through the magnetic enrichment and electrochemical signal enhancement of the GME surface.
3. The electrochemical assay method for determining the kinase activity of T4 polynucleotide based on magnetic nanomaterial as claimed in claim 2, wherein: in step (6), determination of kinase activity of the T4 polynucleotide:
addition of ATP and T4PNK to nucleic acid strand S1Buffer solution, incubation at 37 ℃ for 4 hours, addition of Fe3O4@TiO2Magnetic core-shell nano particle solution, and culturing for 2 hours; then adding AuNPs-S2Incubating the nanoparticle solution at 37 ℃ for 2 hours; then the mixed solution is dripped on the surface of a treated magnetic gold electrode (GME), the electrode is washed by PBS buffer solution, and [ Ru (NH) is dripped3)6]3+The surface of the electrode of the electroactive substance realizes the amplification of electrochemical response signals through magnetic enrichment; and measuring an electrochemical response signal by using an electrochemical workstation, and quantitatively determining the activity of the T4PNK according to the magnitude of the electrochemical signal.
4. The electrochemical assay method for determining the kinase activity of T4 polynucleotide based on magnetic nanomaterial as claimed in claim 3, wherein: in step (1), the nucleic acid strand S1 is 20 bases in length, the nucleic acid strand S2 is 19 bases in length, and the nucleic acid strand S1The dosage and the concentration of the composition are respectively 10 mu L and 10 OD/mL; in step (3), Fe3O4@TiO2The diameter of the magnetic core-shell nano-particle is 400 nm.
5. The electrochemical assay method for determining the kinase activity of T4 polynucleotide based on magnetic nanomaterial according to claim 4, wherein: in the step (5), the concentration of ATP is 10mM, and the concentration of T4PNK is 0.0001-10U/mL; AuNP-S2The dosage and concentration of the composition are respectively 10 mu L and 15 mu M; the time of phosphorylation reaction of S1 is 4 h; s1Modification to Fe3O4@TiO2The surface time is 2 h; the hybridization time of S1 and S2 is 2 h; the reaction temperature and the hybridization temperature in the system were 37 ℃.
6. The electrochemical assay method for determining the kinase activity of T4 polynucleotide based on magnetic nanomaterial according to claim 4, wherein: in the step (6), the working electrode is a magnetic gold electrode with the diameter of 3 mm; [ Ru (NH) in electrochemical measurement System3)6]3+The dosage and concentration of the composition are respectively 100 mu L and 50 mu M; fe3O4@TiO2-S1/S2-AuNPs complex and [ Ru (NH)3)6]3+The electroactive indicator is enriched on the surface of the electrode through magnetism; the T4PNK activity measurement technique is differential pulse voltammetry.
7. The electrochemical assay method for determining the kinase activity of T4 polynucleotide based on magnetic nanomaterial of claim 6, wherein: in step (6), the electrochemical signal amplification technique is based on Fe3O4@TiO2Magnetic core-shell nanoparticles and AuNPs nanoparticles.
8. The electrochemical assay method for determining the kinase activity of T4 polynucleotide based on magnetic nanomaterial of claim 7, wherein: in the step (6), the working electrode is a magnetic gold electrode; the magnetic gold electrode realizes the enhancement of electrochemical signals through magnetic enrichment.
Technical Field
The invention relates to the technical field of biochemical analysis or biochemistry, in particular to an electrochemical analysis method for determining T4 polynucleotide kinase activity based on a magnetic nano material.
Background
T4 Polynucleotide kinase (T4 polynucleotide kinase, T4 PNK) is a protein encoded by the pseT gene of bacteriophage, has 5 'kinase activity, can catalyze phosphorylation of the 5' hydroxyl end of nucleic acid, and is closely related to normal cell activities such as DNA recombination, replication, and damage repair. In addition, T4PNK is an important molecular biology tool, and the discovery and application of T4PNK promote the development of molecular biology to some extent. At present, T4PNK has become an indispensable tool enzyme in genetic engineering and biological analysis research, and is further used for the research of nucleic acid damage repair and enzyme inhibitors. Therefore, the determination of the activity of T4PNK is of great significance in the fields of biochemistry and molecular biology.
The magnetic nanoparticles have both nanomaterial properties and magnetic properties. Ferroferric oxide (Fe)3O4) The magnetic nano particles have the characteristics of superparamagnetism, large specific surface area, excellent adsorption performance, low toxicity, insufficient coordination of surface atoms and the like, and are often used as carriers or magnetic cores of some composite materials in enrichment and separation processes. Nano titanium dioxide (TiO)2) Is a novel inorganic semiconductor material, has the characteristics of large specific surface area, good biocompatibility, strong adsorption capacity, good conductivity, strong chemical inertness, low manufacturing cost and the like, and has wide application prospect in the aspects of selective enrichment of phosphorylated protein and photocatalytic activity. Using magnetic Fe3O4As a nucleus, carrying TiO2Nano shell material, Fe prepared3O4@TiO2The core-shell nano composite material can not only retain TiO2The nano material has high catalytic activity, can maintain the strong magnetism of the magnetic nuclear material, and realizes the high selectivity and specificity enrichment and analysis of phosphorylated protein/polypeptide.
Measurement ofThe method for the activity of T4PNK is mainly a radioactive isotope32P, polyacrylamide gel electrophoresis, autoradiography, and the like. These methods generally have the disadvantages of discontinuity, time and labor consumption, complex operation, high quality personnel requirement, easy radioactive pollution and the like. In recent years, some new detection methods for T4PNK activity have been developed, such as electrochemical methods, quartz crystal microbalance techniques, chemiluminescence methods, fluorescence methods, single molecule fluorescence imaging techniques, and the like. Although the method has high sensitivity, the operation process is complicated, the cost is high, and the application of the method is limited to a certain extent. Aiming at the defects or shortcomings of the existing determination method, a novel, simple and convenient T4PNK activity detection method needs to be developed.
Currently, there is a lack of an electrochemical assay for determining T4 polynucleotide kinase activity based on magnetic nanomaterials that achieves highly sensitive, rapid and quantitative determination of T4PNK activity.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide an electrochemical analysis method for determining the activity of T4 polynucleotide kinase based on a magnetic nano material, which realizes high sensitivity, rapidness and quantitative determination of the activity of T4 PNK.
In order to achieve the technical purpose, the technical scheme adopted by the invention is as follows: the invention discloses an electrochemical analysis method for determining T4 polynucleotide kinase activity based on a magnetic nano material, which comprises the following steps: (1) designing an oligonucleotide sequence;
(2)Fe3O4magnetic nanoparticles;
(3)Fe3O4@TiO2magnetic core-shell nanoparticles: using Fe3O4@TiO2Magnetic core-shell nanoparticles, in the presence of ATP and T4PNK, the 5' end of a nucleic acid chain S1 is phosphorylated and then is reacted with TiO2Specific reaction, binding to Fe3O4@TiO2The surfaces of the magnetic nanoparticles;
(4) preparing AuNPs-S2 nanoparticles;
(5) construction of an electrochemical biosensor
Adding ATP and T4PNK into nucleic acid chain S1 buffer solution, incubating at 37 deg.C for 4 hr, and adding Fe3O4@TiO2Incubating the magnetic core-shell nanoparticle solution for 4 hours; then adding AuNPs-S2Incubating the nanoparticle solution at 37 ℃ for 2-3 hours; then the mixed solution is dripped on the surface of the treated magnetic gold electrode GME, and [ Ru (NH) is dripped after the electrode is washed by PBS buffer solution3)6]3+An electroactive species that measures an electrochemical response signal of the electrode;
(6) the kinase activity of the T4 polynucleotide is measured, an electrochemical workstation is used for testing in a three-electrode system, differential pulse voltammetry DPV is adopted for quantification, and a standard curve of the relation between the DPV peak current and the T4PNK activity is drawn.
Further, in the step (1), the nucleic acid strand S1 has the nucleotide sequence shown in SEQ ID No. 1; the nucleic acid strand S2 has a nucleotide sequence shown in SEQ ID No. 2;
in the step (2), firstly, a hydrothermal method is adopted to prepare Fe3O4Magnetic nanoparticles of FeCl3Dissolving in ethylene glycol, adding NaAc and polyethylene glycol, stirring for dissolving, transferring to a polytetrafluoroethylene autoclave, reacting at 200 deg.C for 8 hr, cooling to room temperature, washing with ethanol for several times, magnetically separating, and drying at room temperature to obtain Fe3O4Magnetic nanoparticles;
in the step (3), glacial acetic acid and butyl titanate are dissolved in ethanol, and Fe is added3O4Adding polyethylene glycol and urea after ultrasonic dispersion of nano particles, stirring and dissolving, transferring the mixture into a reaction container, reacting for 8 hours at 180 ℃, filtering precipitates, washing the precipitates with ethanol for a plurality of times, and drying for 12 hours at 80 ℃ to obtain Fe3O4@TiO2Magnetic core-shell nanoparticles;
in step (4), AuNPs-S2Preparation of nanoparticles
Dissolving a nucleic acid chain S2 in a PBS buffer solution, adding an AuNPs solution, incubating for 4 hours at 37 ℃, adding a colloidal solution, standing for 4 hours, washing with the PBS buffer solution, and performing centrifugal separation to obtain AuNPs-S2 nanoparticles;
in the step (5), the step (c),
addition of gold nanoparticle-nucleic acid strand S2Complex (AuNPs-S)2) AuNPs are modified to Fe by specific hybridization between nucleic acid strands S1 and S23O4@TiO2Fe is formed on the surface of the magnetic nanoparticles3O4@TiO2-S1/S2-AuNPs complex;
in step (6), hexaaminoruthenium [ Ru (NH) ] is applied to the working electrode3)6 3+]The T4PNK activity is quantitatively measured through magnetic enrichment and electrochemical signal enhancement of the GME surface as an electroactive indicator.
Further, in step (6), determination of kinase activity of T4 polynucleotide
ATP and T4PNK were added to a nucleic acid strand S1 buffer solution, incubated at 37 ℃ for 4 hours, and Fe was added3O4@TiO2Magnetic core-shell nano particle solution, and culturing for 2 hours; then adding AuNPs-S2 nano particle solution, and incubating for 2 hours at 37 ℃; then the mixed solution is dripped on the surface of a treated magnetic gold electrode (GME), the electrode is washed by PBS buffer solution, and [ Ru (NH) is dripped3)6]3+The surface of the electrode of the electroactive substance realizes the amplification of electrochemical response signals through magnetic enrichment; and measuring an electrochemical response signal by using an electrochemical workstation, and quantitatively determining the activity of the T4PNK according to the magnitude of the electrochemical signal.
Further, in the step (1), the nucleic acid strand S1 has a length of 20 bases, the nucleic acid strand S2 has a length of 19 bases, and the nucleic acid strand S1 is used in an amount and at a concentration of 10. mu.L and 10OD/mL, respectively; in step (3), Fe3O4@TiO2The diameter of the magnetic core-shell nano-particle is 400 nm.
Further, in the step (5), the concentration of ATP is 10mM, and the concentration of T4PNK is 0.0001-10U/mL; the dosage and concentration of AuNP-S2 are respectively 10 muL and 15 muM; the time of phosphorylation reaction of S1 is 4 h; modification of S1 to Fe3O4@TiO2The surface time is 2 h; the hybridization time of S1 and S2 is 2 h; the reaction temperature and the hybridization temperature in the system were 37 ℃.
Further, in the step (6), the working electrode is a magnetic gold electrode with the diameter of 3 mm; [ Ru (NH) in electrochemical measurement System3)6]3+The dosage and concentration of the composition are respectively 100 mu L and 50 mu M; fe3O4@TiO2-S1/S2-AuNPs complex and [ Ru (NH)3)6]3+The electroactive indicator is enriched on the surface of the electrode through magnetism; the T4PNK activity measurement technique is differential pulse voltammetry.
Further, in step (6), the electrochemical signal amplification technique is based on Fe3O4@TiO2Magnetic core-shell nanoparticles and AuNPs nanoparticles.
Further, in the step (6), the working electrode is a magnetic gold electrode; the magnetic gold electrode realizes the enhancement of electrochemical signals through magnetic enrichment.
Has the advantages that: the invention realizes high-sensitivity, rapid and quantitative determination of the activity of T4 PNK.
Compared with the prior art, the invention has the following advantages:
(1) the invention provides an electrochemical technology for detecting T4Polynucleotide kinase activity;
(2) the invention utilizes Fe3O4@TiO2The sensitivity of the determination of the activity of T4PNK is improved by the double signal amplification technology of the magnetic core-shell nano particles and the AuNPs nano particles;
(3) the invention utilizes the magnetic gold electrode to realize the enhancement of electrochemical signals through magnetic enrichment;
(4) the invention designs DNA with a specific sequence, and improves the selectivity and specificity for detecting the activity of T4 PNK;
(5) the electrochemical biosensor prepared by the invention can be used for T4PNK inhibitors EDTA and Na2HPO4And (NH)4)2SO4Detection of (3).
Drawings
FIG. 1 is a schematic diagram of the preparation technique and detection principle of the magnetic nanomaterial of the present invention for determining the kinase activity of T4 polynucleotide.
FIG. 2 is a standard graph of the activity of T4 polynucleotide kinase measured using the technique of the present invention, with the activity of T4PNK in U/mL on the abscissa and peak current in μ A in DPV response on the ordinate.
Detailed Description
The invention is further illustrated by the following examples. It should be understood that these examples are illustrative and exemplary of the present invention, and are not intended to limit the scope of the present invention in any way.
Example 1
The invention discloses an electrochemical method for determining the activity of T4 polynucleotide kinase based on a magnetic nano material
The invention is based on Fe3O4@TiO2The principle of the method for detecting the activity of T4PNK by using the magnetic core-shell nano-particles and AuNPs dual signal amplification technology is shown in figure 1. First of all, Fe3O4@TiO2Magnetic core-shell nano-particle, ATP and T4PNK, nucleic acid chain S15' phosphorylation of (a), terminal phosphorylated S1 by reaction with TiO2Specific reaction, modification to Fe3O4@TiO2The surface of the magnetic nanoparticles. Then adding AuNPs-S2Nanoparticles, AuNPs, modified to Fe due to hybridization reaction between nucleic acid strands S1 and S23O4@TiO2Fe is formed on the surface of the magnetic nanoparticles3O4@TiO2-S1/S2-AuNPs complex. Finally, magnetic gold electrode (GME) is used as working electrode, hexa-amino ruthenium [ Ru (NH)3)6 3+]Fe formed as an electroactive indicator3O4@TiO2-S1/S2-AuNPs/[Ru(NH3)6]3+The complex realizes the amplification of electrochemical response signals on the surface of the electrode through magnetic enrichment. Realizing T pair according to the magnitude of electrochemical response signal4Quantitative measurement of PNK activity.
Example 2
Oligonucleotide sequence design
The designed oligonucleotide sequence is synthesized by Shanghai Sangon bioengineering Co., Ltd, purified and checked by HPLC, and freeze-dried. The designed oligonucleotide sequence of the invention is as follows: the nucleic acid strand S1 has a nucleotide sequence shown in SEQ ID No. 1; the nucleic acid strand S2 has a nucleotide sequence shown in SEQ ID No. 2;
nucleic acid strand S1: 5 '-SH-CACTTGGTTGGTGTGGTTGG-3';
nucleic acid strand S2: 5'-ACACCAACCAAGTGATGAT-3', respectively; the oligonucleotides were dissolved in ultrapure sterile water and stored at-18 ℃ until use.
Example 3
Fe3O4@TiO2Preparation of magnetic core-shell nanoparticles
0.615g FeCl was weighed3·6H2Dissolving O in 20mL of ethylene glycol, adding 1.8g of NaAc and 0.5g of polyethylene glycol, stirring the solution, transferring the solution to a 100mL stainless steel high-pressure reaction kettle with a polytetrafluoroethylene lining, reacting at 200 ℃ for 8 hours, cooling to room temperature, washing with ethanol for a plurality of times, performing magnetic separation, and air-drying at room temperature to obtain Fe3O4Magnetic nanoparticles. Dissolving 9.6mL of glacial acetic acid and 6.8mL of butyl titanate in 60mL of ethanol, and adding 0.4g of Fe3O4Magnetic nanoparticles, ultrasonic dispersed for 15min, added 2.4g polyethylene glycol and 3.6g urea, stirred electrically for 1 hour, then the mixture was transferred to a reaction vessel and crystallized at 180 ℃ for 8 hours. After cooling to room temperature, the precipitate was filtered and washed several times with ethanol and dried at 80 ℃ for 12 hours to give Fe3O4@TiO2Magnetic core-shell nanoparticles.
Example 4
Preparation of AuNPs-S2 nanoparticles
The nucleic acid strand S2 was dissolved in 10mM PBS buffer (containing 500. mu.M tris (2-carboxyethyl) phosphine hydrochloride), transferred to 100mM PBS buffer pH 7.4 (containing 0.1% Tween-20 and 200mM NaCl), added to the AuNPs solution, and incubated at 37 ℃ for 4 hours. 0.3M NaCl salinized colloidal solution was added and left to stand for 4 hours. Washed three times with 100mM PBS buffer (containing 500mM NaCl) and centrifuged at 10000rpm for 20 minutes to obtain AuNPs-S2 nanoparticles.
Example 5
Preparation of electrochemical biosensor
0.3 μm and 0.05 μm Al for magnetic gold electrode (GME)2O3Grinding and polishing the powder, and ultrasonically washing the powder by using ultrapure water, absolute ethyl alcohol and ultrapure water in sequence; soaking GME in piranha solution for 30min, and washing with ultrapure water; at 0.5M H2SO4Adopting cyclic voltammetry to scan 30 circles of activated electrodes in the solution, wherein the potential range is-0.2-1.6V, the scanning speed is 50mV/s, and N is2And (5) blowing the air for drying for later use.
mu.L of 10OD/mL nucleic acid strand S1 solution was added with 5. mu.L of 1mM ATP and varying concentrations of T4PNK, incubated at 37 ℃ for 4 hours, and 5. mu.L 5 mg/mLFe was added3O4@TiO2Magnetic core-shell nano particle solution, and culturing for 2 hours; after washing with 10mM PBS buffer pH 7.4, 10. mu.L of 15. mu.M AuNPs-S2 nanoparticle solution was added, and incubation was performed at 37 ℃ for 2 hours; 10 μ L of the above reaction mixture was applied dropwise to the surface of a treated magnetic gold electrode, the electrode was washed with 10mM PBS buffer pH 7.4, and 100 μ L of 50 μ M [ Ru (NH) was added dropwise3)6]3+The electroactive material was washed with 10mM PBS buffer pH 7.4 to obtain the T4PNK electrochemical biosensor.
Example 6
Example 6 differs from example 5 in that:
preparation of electrochemical biosensor
Adding ATP and T4PNK into nucleic acid chain S1 buffer solution, incubating at 37 deg.C for 4 hr, and adding Fe3O4@TiO2Incubating the magnetic core-shell nanoparticle solution for 4 hours; then adding AuNPs-S2Incubating the nanoparticle solution at 37 ℃ for 3 hours; then the mixed solution is dripped on the surface of the treated magnetic gold electrode GME, and [ Ru (NH) is dripped after the electrode is washed by PBS buffer solution3)6]3+An electroactive species, measuring an electrochemical response signal of the electrode.
Example 7
Example 7 differs from example 5 in that:
preparation of electrochemical biosensor
Adding ATP and T4PNK into nucleic acid chain S1 buffer solution, incubating at 37 deg.C for 4 hr, and adding Fe3O4@TiO2Magnetic core-shell nanoparticlesIncubating the solution for 4 hours; then adding AuNPs-S2Incubating the nanoparticle solution at 37 ℃ for 2.5 hours; then the mixed solution is dripped on the surface of the treated magnetic gold electrode GME, and [ Ru (NH) is dripped after the electrode is washed by PBS buffer solution3)6]3+An electroactive species, measuring an electrochemical response signal of the electrode.
Example 8
Determination of the activity of T4PNK
And (3) testing by using an electrochemical workstation in a three-electrode system, wherein a saturated calomel electrode is used as a reference electrode, a platinum wire electrode is used as a counter electrode, and a magnetic gold electrode is used as a working electrode. The activity of T4PNK is measured by adopting differential pulse voltammetry, 10mM Tris-HCl (pH 7.4,0.1M NaCl) is used as a buffer solution, the potential range is-0.4-0V, the potential amplification is 50mV, and the pulse period is 20 ms. The standard curve of the response peak current of the differential pulse curve and the concentration of T4PNK is shown in figure 2, the peak current and the concentration of T4PNK show good linear relation in the range of 0.0001-10U/mL, and the correlation coefficient R20.9951, the linear equation is ipc(μ a) ═ 0.24log c +1.67, detection limit 0.00003U/mL. Compared with other sensors, the sensor provided by the invention has wider linear range and lower detection limit, and adopts Fe3O4@TiO2The magnetic core-shell nano particle and AuNPs double signal amplification technology can realize the quantitative and sensitive determination of the T4PNK activity.
Example 9
Assay for inhibitors of T4PNK activity
Different concentrations of EDTA and Na inhibitors2HPO4And (NH)4)2SO4Mixed with T4PNK buffer solution, the relative activity of T4PNK is obviously reduced along with the increase of the concentration of the inhibitor in the same experimental method. When the three inhibitors were added at concentrations of 12.5mM, 7mM and 6 mM, respectively, the relative activity of T4PNK decreased by 50%, indicating that the method can be used in the assay for the detection of the T4PNK inhibitor.
The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the foregoing description only for the purpose of illustrating the principles of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined by the appended claims, specification, and equivalents thereof.
SEQUENCE LISTING
<110> university of national Yunnan
<120> electrochemical analysis method for determining T4 polynucleotide kinase activity based on magnetic nano material
<130> 2020
<160> 2
<170> PatentIn version 3.3
<210> 1
<211> 22
<212> DNA
<213> Artificial sequence (nucleic acid strand S1)
<400> 1
shcacttggttggtgtggttgg 22
<210> 2
<211> 19
<212> DNA
<213> Artificial sequence (nucleic acid strand S2)
<400> 2
acaccaacca agtgatgat 19
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