CN113281389A - Preparation method of electrochemical immunosensor based on 2,4, 6-triaminopyrimidine regulation and control graphite-like-phase carbon nitride - Google Patents
Preparation method of electrochemical immunosensor based on 2,4, 6-triaminopyrimidine regulation and control graphite-like-phase carbon nitride Download PDFInfo
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- JMANVNJQNLATNU-UHFFFAOYSA-N oxalonitrile Chemical compound N#CC#N JMANVNJQNLATNU-UHFFFAOYSA-N 0.000 title claims abstract description 65
- JTTIOYHBNXDJOD-UHFFFAOYSA-N 2,4,6-triaminopyrimidine Chemical compound NC1=CC(N)=NC(N)=N1 JTTIOYHBNXDJOD-UHFFFAOYSA-N 0.000 title claims abstract description 64
- 238000002360 preparation method Methods 0.000 title claims abstract description 54
- 230000033228 biological regulation Effects 0.000 title abstract description 4
- 102000012288 Phosphopyruvate Hydratase Human genes 0.000 claims abstract description 89
- 108010022181 Phosphopyruvate Hydratase Proteins 0.000 claims abstract description 89
- 230000001105 regulatory effect Effects 0.000 claims abstract description 45
- OMZSGWSJDCOLKM-UHFFFAOYSA-N copper(II) sulfide Chemical compound [S-2].[Cu+2] OMZSGWSJDCOLKM-UHFFFAOYSA-N 0.000 claims abstract description 41
- 239000002096 quantum dot Substances 0.000 claims abstract description 41
- 239000003550 marker Substances 0.000 claims abstract description 33
- BWFPGXWASODCHM-UHFFFAOYSA-N copper monosulfide Chemical class [Cu]=S BWFPGXWASODCHM-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000002131 composite material Substances 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims abstract description 13
- 229920000877 Melamine resin Polymers 0.000 claims abstract description 12
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000000243 solution Substances 0.000 claims description 82
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 45
- 239000000047 product Substances 0.000 claims description 31
- 229910021642 ultra pure water Inorganic materials 0.000 claims description 30
- 239000012498 ultrapure water Substances 0.000 claims description 30
- 239000008055 phosphate buffer solution Substances 0.000 claims description 25
- 239000008367 deionised water Substances 0.000 claims description 20
- 229910021641 deionized water Inorganic materials 0.000 claims description 20
- 239000000843 powder Substances 0.000 claims description 20
- 238000003756 stirring Methods 0.000 claims description 20
- 238000005406 washing Methods 0.000 claims description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 16
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- 238000002156 mixing Methods 0.000 claims description 13
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- FPQQSJJWHUJYPU-UHFFFAOYSA-N 3-(dimethylamino)propyliminomethylidene-ethylazanium;chloride Chemical compound Cl.CCN=C=NCCCN(C)C FPQQSJJWHUJYPU-UHFFFAOYSA-N 0.000 claims description 10
- 239000007864 aqueous solution Substances 0.000 claims description 10
- 238000006243 chemical reaction Methods 0.000 claims description 10
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- 229910052979 sodium sulfide Inorganic materials 0.000 claims description 10
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 claims description 10
- 238000001291 vacuum drying Methods 0.000 claims description 10
- 239000000427 antigen Substances 0.000 claims description 9
- 102000036639 antigens Human genes 0.000 claims description 9
- 108091007433 antigens Proteins 0.000 claims description 9
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- 229910021397 glassy carbon Inorganic materials 0.000 claims description 6
- XIOUDVJTOYVRTB-UHFFFAOYSA-N 1-(1-adamantyl)-3-aminothiourea Chemical compound C1C(C2)CC3CC2CC1(NC(=S)NN)C3 XIOUDVJTOYVRTB-UHFFFAOYSA-N 0.000 claims description 5
- LXBGSDVWAMZHDD-UHFFFAOYSA-N 2-methyl-1h-imidazole Chemical compound CC1=NC=CN1 LXBGSDVWAMZHDD-UHFFFAOYSA-N 0.000 claims description 5
- 108091003079 Bovine Serum Albumin Proteins 0.000 claims description 5
- NQTADLQHYWFPDB-UHFFFAOYSA-N N-Hydroxysuccinimide Chemical compound ON1C(=O)CCC1=O NQTADLQHYWFPDB-UHFFFAOYSA-N 0.000 claims description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 5
- 229940098773 bovine serum albumin Drugs 0.000 claims description 5
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 claims description 5
- DGLRDKLJZLEJCY-UHFFFAOYSA-L disodium hydrogenphosphate dodecahydrate Chemical compound O.O.O.O.O.O.O.O.O.O.O.O.[Na+].[Na+].OP([O-])([O-])=O DGLRDKLJZLEJCY-UHFFFAOYSA-L 0.000 claims description 5
- GRYOUGKDYRHZJB-UHFFFAOYSA-L disodium sulfate nonahydrate Chemical compound O.O.O.O.O.O.O.O.O.[Na+].[Na+].[O-]S([O-])(=O)=O GRYOUGKDYRHZJB-UHFFFAOYSA-L 0.000 claims description 5
- 238000000227 grinding Methods 0.000 claims description 5
- 238000011534 incubation Methods 0.000 claims description 5
- SURQXAFEQWPFPV-UHFFFAOYSA-L iron(2+) sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Fe+2].[O-]S([O-])(=O)=O SURQXAFEQWPFPV-UHFFFAOYSA-L 0.000 claims description 5
- 238000003760 magnetic stirring Methods 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 229910000402 monopotassium phosphate Inorganic materials 0.000 claims description 5
- 235000019796 monopotassium phosphate Nutrition 0.000 claims description 5
- 239000004570 mortar (masonry) Substances 0.000 claims description 5
- 230000010355 oscillation Effects 0.000 claims description 5
- GNSKLFRGEWLPPA-UHFFFAOYSA-M potassium dihydrogen phosphate Chemical compound [K+].OP(O)([O-])=O GNSKLFRGEWLPPA-UHFFFAOYSA-M 0.000 claims description 5
- LWIHDJKSTIGBAC-UHFFFAOYSA-K potassium phosphate Substances [K+].[K+].[K+].[O-]P([O-])([O-])=O LWIHDJKSTIGBAC-UHFFFAOYSA-K 0.000 claims description 5
- 239000002244 precipitate Substances 0.000 claims description 5
- 230000000630 rising effect Effects 0.000 claims description 5
- 239000001509 sodium citrate Substances 0.000 claims description 5
- HRXKRNGNAMMEHJ-UHFFFAOYSA-K trisodium citrate Chemical compound [Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O HRXKRNGNAMMEHJ-UHFFFAOYSA-K 0.000 claims description 5
- 229940038773 trisodium citrate Drugs 0.000 claims description 5
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 4
- 238000001514 detection method Methods 0.000 abstract description 20
- 239000000463 material Substances 0.000 abstract description 13
- 239000000758 substrate Substances 0.000 abstract description 6
- JYEUMXHLPRZUAT-UHFFFAOYSA-N 1,2,3-triazine Chemical group C1=CN=NN=C1 JYEUMXHLPRZUAT-UHFFFAOYSA-N 0.000 abstract description 5
- 125000004432 carbon atom Chemical group C* 0.000 abstract description 4
- 238000010276 construction Methods 0.000 abstract description 4
- 238000007334 copolymerization reaction Methods 0.000 abstract description 4
- 125000004433 nitrogen atom Chemical group N* 0.000 abstract description 4
- LELOWRISYMNNSU-UHFFFAOYSA-N hydrogen cyanide Chemical compound N#C LELOWRISYMNNSU-UHFFFAOYSA-N 0.000 abstract 2
- 238000002372 labelling Methods 0.000 abstract 1
- 239000002243 precursor Substances 0.000 abstract 1
- 238000004020 luminiscence type Methods 0.000 description 21
- 238000012360 testing method Methods 0.000 description 10
- 230000000171 quenching effect Effects 0.000 description 9
- 238000010791 quenching Methods 0.000 description 8
- 239000012086 standard solution Substances 0.000 description 6
- 229910021607 Silver chloride Inorganic materials 0.000 description 5
- 206010041067 Small cell lung cancer Diseases 0.000 description 5
- 238000002796 luminescence method Methods 0.000 description 5
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 5
- USHAGKDGDHPEEY-UHFFFAOYSA-L potassium persulfate Chemical compound [K+].[K+].[O-]S(=O)(=O)OOS([O-])(=O)=O USHAGKDGDHPEEY-UHFFFAOYSA-L 0.000 description 5
- 238000002165 resonance energy transfer Methods 0.000 description 5
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 5
- 208000000587 small cell lung carcinoma Diseases 0.000 description 5
- 239000000872 buffer Substances 0.000 description 4
- 230000035945 sensitivity Effects 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 102000004190 Enzymes Human genes 0.000 description 2
- 108090000790 Enzymes Proteins 0.000 description 2
- 238000000862 absorption spectrum Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 238000000295 emission spectrum Methods 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 208000002154 non-small cell lung carcinoma Diseases 0.000 description 2
- 238000011896 sensitive detection Methods 0.000 description 2
- 208000029729 tumor suppressor gene on chromosome 11 Diseases 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 206010058467 Lung neoplasm malignant Diseases 0.000 description 1
- 206010027476 Metastases Diseases 0.000 description 1
- 206010028980 Neoplasm Diseases 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 150000005005 aminopyrimidines Chemical class 0.000 description 1
- 239000012491 analyte Substances 0.000 description 1
- 230000004071 biological effect Effects 0.000 description 1
- 239000000090 biomarker Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000002512 chemotherapy Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000013399 early diagnosis Methods 0.000 description 1
- 230000005518 electrochemistry Effects 0.000 description 1
- 238000005837 enolization reaction Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 201000005202 lung cancer Diseases 0.000 description 1
- 208000020816 lung neoplasm Diseases 0.000 description 1
- 239000008204 material by function Substances 0.000 description 1
- 230000009401 metastasis Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 210000002569 neuron Anatomy 0.000 description 1
- 238000005121 nitriding Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000012488 sample solution Substances 0.000 description 1
- 210000002966 serum Anatomy 0.000 description 1
- 230000019491 signal transduction Effects 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000001225 therapeutic effect Effects 0.000 description 1
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
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- G01—MEASURING; TESTING
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- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/28—Electrolytic cell components
- G01N27/30—Electrodes, e.g. test electrodes; Half-cells
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/28—Electrolytic cell components
- G01N27/30—Electrodes, e.g. test electrodes; Half-cells
- G01N27/327—Biochemical electrodes, e.g. electrical or mechanical details for in vitro measurements
- G01N27/3271—Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood
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Abstract
本发明涉及一种基于2,4,6‑三氨基嘧啶调控的类石墨相氮化碳的电化学免疫传感器的制备方法。本发明以构建夹心型电化学传感器的方式，使用2,4,6‑三氨基嘧啶调控的类石墨相氮化碳与神经元特异性烯醇化酶一抗结合形成一抗标记物，以Fe‑ZIF负载硫化铜量子点复合材料与神经元特异性烯醇化酶二抗结合形成二抗标记物，简化了传感器构建过程。通过2,4,6‑三氨基嘧啶与类石墨相氮化碳的前驱体三聚氰胺共聚，准确的将三嗪环结构中的部分氮原子替换成碳原子，改善了类石墨相氮化碳网络结构的电子环境。以2,4,6‑三氨基嘧啶调控的类石墨相氮化碳作为基底发光材料，提供了传感器所需的强且持续稳定的电化学发光信号。使用Fe‑ZIF负载硫化铜量子点用于标记神经元特异性烯醇化酶的二抗作为二抗标记物，构建了夹心猝灭型电化学免疫传感器，实现了对神经元特异性烯醇化酶的超灵敏检测，检测限为21.6 fg mL‑1。The invention relates to a preparation method of an electrochemical immunosensor based on 2, 4, 6-triaminopyrimidine regulation and control of graphitic phase carbon nitride. In the method of constructing a sandwich-type electrochemical sensor, the present invention uses the graphitic phase carbon nitride regulated by 2,4,6-triaminopyrimidine to combine with the neuron-specific enolase primary antibody to form a primary antibody label, and uses Fe- The ZIF-loaded copper sulfide quantum dot composites combined with the neuron-specific enolase secondary antibody to form a secondary antibody marker, which simplified the sensor construction process. Through the copolymerization of 2,4,6-triaminopyrimidine and melamine, the precursor of graphitic carbon nitride, some nitrogen atoms in the triazine ring structure are accurately replaced with carbon atoms, and the network structure of graphitic carbon nitride is improved. electronic environment. The graphitic-like carbon nitride regulated by 2,4,6-triaminopyrimidine was used as the substrate luminescent material to provide the strong and continuous electrochemiluminescence signal required for the sensor. Using Fe-ZIF-loaded copper sulfide quantum dots as a secondary antibody for labeling neuron-specific enolase, a sandwich-quenched electrochemical immunosensor was constructed, and the detection of neuron-specific enolase was realized. Ultrasensitive detection with a detection limit of 21.6 fg mL -1 .
Description
Technical Field
The invention relates to a preparation method of a graphite-like phase carbon nitride electrochemical immunosensor based on 2,4, 6-triaminopyrimidine regulation and control, and particularly relates to a preparation method of a sandwich quenching type electrochemical immunosensor for detecting neuron-specific enolase, which is characterized in that graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine is combined with neuron-specific enolase primary antibody to form a primary antibody marker, and Fe-ZIF loaded copper sulfide quantum dot composite material is used as a secondary antibody marker for marking a secondary antibody of the neuron-specific enolase recognition antibody, so that the sandwich quenching type electrochemical immunosensor for detecting the neuron-specific enolase is prepared, and belongs to the technical field of novel functional materials and biosensing detection.
Background
Lung cancer is one of the most fatal cancers known at present, and is largely classified into Small Cell Lung Cancer (SCLC) and non-small cell lung cancer (NSCLC). Small cell lung cancer is known for its rapid early metastasis and rapid doubling time, and is difficult to treat due to its initial high sensitivity and resistance to chemotherapy. Studies report that neuron-specific enolase (NSE) is a reliable, specific, sensitive serum biomarker for early diagnosis of SCLC, and can assess the progress of patient recovery. Therefore, determination of NSE levels is of great interest for monitoring the progression and therapeutic effect of SCLC in clinical diagnostics. Electrochemiluminescence is a new product combining electrochemistry and luminescence, has the advantages of low background, wide dynamic range, simple and convenient instrument and equipment, sensitive detection and the like, and is widely concerned in the fields of biological analysis, food safety analysis, environmental pollution monitoring and the like.
Graphite-like carbon nitride has unique electronic and energy band structure and good biocompatibility, and is often used as a catalyst or a good carrier due to its simple preparation, good chemical stability and easily controllable properties. In recent years, researchers have focused on the electrochemical luminescence property of graphite-like phase carbon nitride and applied the graphite-like phase carbon nitride to the field of electrochemical immunosensors, but the application of the original graphite-like phase carbon nitride to the field of the immunosensors is greatly limited due to the fact that the electrochemical luminescence is weak and a luminescence signal is unstable. According to the invention, 2,4, 6-triaminopyrimidine is adopted to accurately regulate and control the electrochemiluminescence property of the graphite-like carbon nitride, the electronic arrangement of the graphite-like carbon nitride network structure is changed by introducing different amounts of 2,4, 6-triaminopyrimidine and melamine for copolymerization, part of nitrogen atoms in the triazine ring structure are accurately replaced by carbon atoms, the excellent electrochemiluminescence behavior is endowed, and the application prospect of the graphite-like carbon nitride is greatly expanded.
An electrochemical immunosensor is a type of detection device that determines the concentration of an analyte based on the electrical-to-optical signal transduction characteristics of a substance. Common construction processes require layer-by-layer modification, are complex and affect the biological activity of immune molecules. The invention constructs a novel electrochemical immunosensor based on graphite-like phase carbon nitride accurately regulated and controlled by 2,4, 6-triaminopyrimidine, and the novel electrochemical immunosensor is used for detecting neuron specific enolase. The graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine is used as a substrate luminescent material, and the graphite-like phase carbon nitride has good biocompatibility, stable signals and strong anti-interference capability, so that the graphite-like phase carbon nitride is firstly combined with primary antibody of neuron-specific enolase to form a primary antibody marker. In addition, the Fe-ZIF loaded copper sulfide quantum dots are used as quenching materials, so that a good luminescent signal quenching effect can be realized. The reason is that the ultraviolet absorption spectrum of the Fe-ZIF loaded copper sulfide quantum dot is greatly overlapped with the regulated electrochemical luminescence emission spectrum of the graphite-like phase carbon nitride, so that efficient quenching can be realized based on the resonance energy transfer principle. The Fe-ZIF loaded copper sulfide quantum dots are used for marking secondary antibodies of neuron-specific enolase as secondary antibody markers, so that the ultra-sensitive detection of the neuron-specific enolase is realized, and the detection limit is 21.6 fg mL-1. Compared with the conventional sensor, the electrochemical immunosensor constructed by the invention has the advantages that the number of constructed layers is reduced,the process of constructing the sensor is simple and easy. Based on the excellent performance of the material and a simplified detection method, the electrochemical immunosensor provided by the invention has the advantages of high sensitivity, low detection limit and good stability. Based on the above findings, the inventors have completed the present invention.
Disclosure of Invention
One of the purposes of the invention is to adopt the graphite-like phase carbon nitride accurately regulated and controlled by 2,4, 6-triaminopyrimidine as a substrate luminescent material, accurately replace nitrogen atoms in triazine ring structures with carbon atoms, endow the triazine ring structures with excellent electrochemical luminescence behavior, good biocompatibility, stable electrochemical signals and excellent anti-interference capability, enable the triazine ring structures to be connected with primary antibodies of neuron-specific enolase to form stable primary antibody markers, and simplify the construction process of the sensor.
The invention also aims to use Fe-ZIF loaded copper sulfide quantum dots as quenching materials, and because the ultraviolet absorption spectrum of the Fe-ZIF loaded copper sulfide quantum dots is greatly overlapped with the electrochemical luminescence emission spectrum of the modified graphite-like carbon nitride, the high-efficiency quenching can be realized based on resonance energy transfer, and a novel resonance energy transfer donor-acceptor pair is provided for constructing an electrochemical immunosensor.
The invention also aims to provide a preparation method of the novel sandwich type electrochemical immunosensor based on resonance energy transfer.
The fourth purpose of the invention is to realize the construction of the electrochemical immunosensor and sensitively detect the neuron-specific enolase, and the detection limit is 21.6 fg mL-1The application of the electrochemical luminescence sensor in detecting neuron-specific enolase is achieved.
Technical scheme of the invention
1. A preparation method of an electrochemical immunosensor based on 2,4, 6-triaminopyrimidine-regulated graphite-like-phase carbon nitride is characterized by comprising the following steps:
(1) preparation of graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine
Preparing graphite-like carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine by copolymerizing melamine and 2,4, 6-triaminopyrimidine, fully and uniformly mixing 1 g of melamine and 10-50 mg of 2,4, 6-triaminopyrimidine in an agate mortar for grinding, then placing the mixture in a crucible with a cover, and placing the crucible in a muffle furnace for 5 ℃ for min-1Raising the temperature rising rate to 550 ℃, keeping heating for 4 h, and obtaining the graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine, wherein other conditions are the same when the 2,4, 6-triaminopyrimidine is not added, and the original graphite-like phase carbon nitride is prepared;
(2) preparation of primary anti-marker of graphite-like phase carbon nitride combined neuron-specific enolase recognition antibody regulated and controlled by 2,4, 6-triaminopyrimidine
5-20 microgram mL-1The primary antibody of the neuron-specific enolase is activated by using 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) at 4 ℃, and then is incubated with the graphite-like carbon nitride regulated by 2,4, 6-triaminopyrimidine for 6 hours at 4 ℃ to obtain a primary antibody marker of the graphite-like carbon nitride regulated by 2,4, 6-triaminopyrimidine and combined with the neuron-specific enolase recognition antibody;
(3) preparation of Fe-ZIF
Firstly, dissolving 1-3 g of 2-methylimidazole in 30 mL of anhydrous methanol, and marking as a solution A; in addition, 0.1-0.5 g of ferrous sulfate heptahydrate and 0.6-1 g of zinc nitrate hexahydrate are mixed and dissolved in 30 mL of anhydrous methanol and marked as solution B; mixing the two solutions, stirring uniformly, continuously stirring at 35 ℃ for reacting for 4 hours, centrifuging the mixed solution after the reaction is finished, collecting the obtained product, washing and centrifuging for 3 times by using anhydrous methanol, and drying the washed product in a vacuum drying oven at 60 ℃ overnight to obtain Fe-ZIF powder;
(4) preparation of copper sulfide quantum dots
Dissolving 20-50 mg of sodium sulfate nonahydrate in 3 mL of deionized water to obtain a sodium sulfide solution for later use, dissolving 50-100 mg of copper chloride and 80-100 mg of trisodium citrate in 300 mL of ultrapure water, magnetically stirring to obtain a light blue transparent solution, heating the fully dissolved solution, reacting for 30 min at 90 ℃, slowly dropwise adding the sodium sulfide solution in the heating process, observing that the solution gradually becomes dark green and precipitates are generated in the process, centrifuging the suspension after the reaction is finished, collecting the obtained product, washing and centrifuging for 3 times by using the ultrapure water, dissolving the washed copper sulfide quantum dot suspension in 5 mL of deionized water, and storing for later use at 4 ℃;
(5) preparation of Fe-ZIF loaded copper sulfide quantum dot composite material
Dissolving 50-100 mg of prepared Fe-ZIF powder in 300 mL of deionized water, performing magnetic stirring to fully disperse and dissolve the powder, then slowly dropwise adding the copper sulfide quantum dot suspension to fully load the copper sulfide quantum dots with Fe-ZIF, stirring for 8 hours, centrifuging the mixed solution, collecting the obtained product, washing and centrifuging for 3 times with deionized water, and drying the washed product in a vacuum drying oven at 60 ℃ overnight to obtain the Fe-ZIF loaded copper sulfide quantum dot composite material;
(6) preparation of PBS buffer solution
11.94 g of disodium hydrogen phosphate dodecahydrate were taken out and dissolved in a 500 mL volumetric flask so as to be prepared into a solution having a concentration of 1/15 mol L-1As an aqueous solution of (a); 4.54 g of monopotassium phosphate is taken and fixed to a 500 mL volumetric flask, and the volume is configured to be 1/15 mol L-1As solution b; mixing the solution A and the solution B in proportion to prepare a series of PBS (phosphate buffer solution) with the pH value of 6.0-8.0;
(7) preparation of secondary antibody marker of Fe-ZIF loaded copper sulfide quantum dot combined with neuron specific enolase recognition antibody
20-100 μ L of neuron-specific enolase secondary antibody (10 μ g mL)-1) Adding 1 mL to 1-3 mg mL-1Carrying out oscillation incubation for 12 h at 4 ℃ in an aqueous solution of the Fe-ZIF-loaded copper sulfide quantum dot composite material, centrifuging, and dispersing the obtained product in 1 mL of PBS to obtain a secondary antibody marker solution of the Fe-ZIF-loaded copper sulfide quantum dot combined with a neuron-specific enolase recognition antibody;
(8) preparation of electrochemical immunosensor
1) Throwing with aluminum oxidePolishing a glassy carbon electrode with the diameter of 4 mm by using polishing powder, cleaning with ultrapure water, and carrying out 6 mu L and 0.5-2.5 mg mL treatment on the polished glassy carbon electrode-1The primary-antibody marker solution of the graphite-like phase carbon nitride combined with neuron-specific enolase recognition antibody regulated and controlled by 2,4, 6-triaminopyrimidine is dripped on the surface of the electrode and dried at room temperature;
2) continuously dropwise adding bovine serum albumin solution with the mass fraction of 0.1% to the surface of the electrode, cleaning with ultrapure water, and airing at room temperature;
3) continuously dropwise adding 6 muL and 0.00005-100 ng mL-1A series of neuron specific enolase antigens with different concentrations are applied to the surface of the electrode, incubated for 2 hours, rinsed with ultrapure water and dried at room temperature;
4) and finally, dropwise adding 6 muL of Fe-ZIF loaded copper sulfide quantum dots and a second antibody marker solution combined with the neuron specific enolase recognition antibody, washing with ultrapure water, and airing at room temperature to obtain the electrochemical immunosensor for detecting the neuron specific enolase.
2. The detection method of the electrochemical immunosensor comprises the following steps:
(1) Ag/AgCl is used as a reference electrode, a platinum wire is used as a counter electrode, the prepared electrochemical luminescence sensor is used as a working electrode and is correctly connected in a cassette of a chemiluminescence detector, an electrochemical workstation is connected with the chemiluminescence detector, the high voltage of a photomultiplier is set to be 500-800V, and the electrochemical luminescence sensor contains 20-100 mmoL L-1The test was performed in a PBS buffer solution of potassium persulfate;
(2) detecting the neuron specific enolase standard solution by an electrochemical luminescence method, wherein the voltage test range is-1.6-0V;
(3) observing the electrochemiluminescence intensity of the sensor before and after the addition of the neuron-specific enolase, recording the linear relation between the electrochemiluminescence intensity value and the concentration of the neuron-specific enolase, and drawing a working curve;
(4) and replacing the neuron-specific enolase antigen standard solution with the neuron-specific enolase antigen sample solution to be detected for detection.
The sensor is used for specific enolization of neuronsThe linear detection range of the enzyme antigen is 0.00005-100 ng mL-1The detection limit is 21.6 fg mL-1。
The chemicals required for the synthesis were all purchased at the local reagent store and were not reprocessed.
Advantageous results of the invention
(1) According to the invention, the graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine is used as a substrate luminescent material, and part of nitrogen atoms in the graphite-like phase carbon nitride triazine ring structure are accurately replaced by carbon atoms, so that excellent electrochemical luminescence behavior is given to the material, the overall electron distribution of the material is greatly improved, the defects that the original graphite-like phase carbon nitride electrochemical luminescence signal is weak and the luminescence signal is unstable are overcome, and the method has important significance for the extended application of the graphite-like phase carbon nitride.
(2) The invention provides a novel donor-acceptor pair for resonance energy transfer, which is constructed by using graphite-like carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine as a substrate luminescent material and using Fe-ZIF loaded copper sulfide quantum dots as a quenching material.
(3) The invention provides a novel method for constructing an electrochemical immunosensor. According to the method, the primary antibody and the secondary antibody of the substance to be detected are respectively marked by the substrate luminescent material and the quenching material, and then the antigen to be detected is identified, so that the preparation of the sensor is simpler and more convenient, and the prepared sensor has good stability, high sensitivity and good reproducibility.
(4) The electrochemical immunosensor prepared by the invention sensitively detects the neuron specific enolase, and the detection range is 0.00005-100 ng mL-1The detection limit is 21.6 fg mL-1And the detection with simplicity, convenience, rapidness, high sensitivity, high specificity and high stability can be realized.
Detailed Description
EXAMPLE 1 preparation of electrochemical immunosensor
(1) Preparation of graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine
Copolymerization of melamine and 2,4, 6-triaminopyrimidine to prepare 2,4, 6-trisThe graphite-like phase carbon nitride controlled by aminopyrimidine is prepared by mixing 1 g of melamine and 10 mg of 2,4, 6-triaminopyrimidine uniformly and thoroughly in an agate mortar for grinding, then placing the mixture in a crucible with a cover, and heating in a muffle furnace for 5 ℃ for min-1Raising the temperature rising rate to 550 ℃, keeping heating for 4 h, and obtaining the graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine, wherein other conditions are the same when the 2,4, 6-triaminopyrimidine is not added, and the original graphite-like phase carbon nitride is prepared;
(2) preparation of primary anti-marker of graphite-like phase carbon nitride combined neuron-specific enolase recognition antibody regulated and controlled by 2,4, 6-triaminopyrimidine
5 microgram mL-1The primary antibody of the neuron-specific enolase is activated by using 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) at 4 ℃, and then is incubated with the graphite-like carbon nitride regulated by 2,4, 6-triaminopyrimidine for 6 hours at 4 ℃ to obtain a primary antibody marker of the graphite-like carbon nitride regulated by 2,4, 6-triaminopyrimidine and combined with the neuron-specific enolase recognition antibody;
(3) preparation of Fe-ZIF
Firstly, dissolving 1 g of 2-methylimidazole in 30 mL of anhydrous methanol, and marking as a solution A; in addition, 0.1 g of ferrous sulfate heptahydrate and 0.6 g of zinc nitrate hexahydrate are mixed and dissolved in 30 mL of anhydrous methanol, and the solution B is marked; mixing the two solutions, stirring uniformly, continuously stirring at 35 ℃ for reacting for 4 hours, centrifuging the mixed solution after the reaction is finished, collecting the obtained product, washing and centrifuging for 3 times by using anhydrous methanol, and drying the washed product in a vacuum drying oven at 60 ℃ overnight to obtain Fe-ZIF powder;
(4) preparation of copper sulfide quantum dots
Dissolving 20 mg of sodium sulfate nonahydrate in 3 mL of deionized water to obtain a sodium sulfide solution for later use, dissolving 50 mg of copper chloride and 80 mg of trisodium citrate in 300 mL of ultrapure water, magnetically stirring to obtain a light blue transparent solution, heating the fully dissolved solution, reacting for 30 min at 90 ℃, slowly dropwise adding the sodium sulfide solution in the heating process, wherein the solution gradually becomes dark green and precipitates are generated in the process, centrifuging the suspension after the reaction is finished, collecting the obtained product, washing and centrifuging for 3 times by using the ultrapure water, dissolving the washed copper sulfide quantum dot suspension in 5 mL of deionized water, and storing for later use at 4 ℃;
(5) preparation of Fe-ZIF loaded copper sulfide quantum dot composite material
Dissolving the prepared 50 mg of Fe-ZIF powder in 300 mL of deionized water, carrying out magnetic stirring to fully dissolve and disperse the powder, then slowly dropwise adding the copper sulfide quantum dot suspension to fully load the copper sulfide quantum dots with Fe-ZIF, stirring for 8 h, centrifuging the mixed solution, collecting the obtained product, washing and centrifuging for 3 times with deionized water, and drying the washed product in a vacuum drying oven at 60 ℃ overnight to obtain the Fe-ZIF loaded copper sulfide quantum dot composite material;
(6) preparation of PBS buffer solution
11.94 g of disodium hydrogen phosphate dodecahydrate were taken out and dissolved in a 500 mL volumetric flask so as to be prepared into a solution having a concentration of 1/15 mol L-1As an aqueous solution of (a); 4.54 g of monopotassium phosphate is taken and fixed to a 500 mL volumetric flask, and the volume is configured to be 1/15 mol L-1As solution b; mixing the solution A and the solution B in proportion to prepare a series of PBS (phosphate buffer solution) with the pH value of 6.0-8.0;
(7) preparation of secondary antibody marker of Fe-ZIF loaded copper sulfide quantum dot combined with neuron specific enolase recognition antibody
mu.L of a secondary antibody to neuron-specific enolase (10. mu.g mL)-1) Added to 1 mL of 1 mg mL-1Carrying out oscillation incubation for 12 h at 4 ℃ in an aqueous solution of the Fe-ZIF-loaded copper sulfide quantum dot composite material, centrifuging, and dispersing the obtained product in 1 mL of PBS to obtain a secondary antibody marker solution of the Fe-ZIF-loaded copper sulfide quantum dot combined with a neuron-specific enolase recognition antibody;
(8) preparation of electrochemical immunosensor
1) Polishing a glassy carbon electrode with the diameter of 4 mm by using aluminum oxide polishing powder, cleaning by using ultrapure water, and polishing by using 6 muL and 0.5 mg mL-12,4, 6-triaminopyrimidine-regulated graphite-like phase carbon nitride-binding neuron-specific enolizationDropwise adding a primary antibody marker solution of the enzyme recognition antibody to the surface of the electrode, and airing at room temperature;
2) continuously dropwise adding bovine serum albumin solution with the mass fraction of 0.1% to the surface of the electrode, cleaning with ultrapure water, and airing at room temperature;
3) continuously dropwise adding 6 muL and 0.00005-100 ng mL-1A series of neuron specific enolase antigens with different concentrations are applied to the surface of the electrode, incubated for 2 hours, rinsed with ultrapure water and dried at room temperature;
4) and finally, dropwise adding 6 muL of Fe-ZIF loaded copper sulfide quantum dots and a second antibody marker solution combined with the neuron specific enolase recognition antibody, washing with ultrapure water, and airing at room temperature to obtain the electrochemical immunosensor for detecting the neuron specific enolase.
EXAMPLE 2 preparation of electrochemical immunosensor
(1) Preparation of graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine
2,4, 6-triaminopyrimidine-regulated graphite-like carbon nitride is prepared by copolymerizing melamine and 2,4, 6-triaminopyrimidine, 1 g of melamine and 30 mg of 2,4, 6-triaminopyrimidine are mixed sufficiently and uniformly in an agate mortar for grinding, then the mixture is placed in a crucible with a cover and is put in a muffle furnace for 5 ℃ for min-1Raising the temperature rising rate to 550 ℃, keeping heating for 4 h, and obtaining the graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine, wherein other conditions are the same when the 2,4, 6-triaminopyrimidine is not added, and the original graphite-like phase carbon nitride is prepared;
(2) preparation of primary anti-marker of graphite-like phase carbon nitride combined neuron-specific enolase recognition antibody regulated and controlled by 2,4, 6-triaminopyrimidine
10 microgram mL-1The primary antibody of the neuron-specific enolase is activated by using 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) at 4 ℃, and then is incubated with the graphite-like carbon nitride regulated by 2,4, 6-triaminopyrimidine for 6 hours at 4 ℃ to obtain the primary antibody of the graphite-like carbon nitride combined with the neuron-specific enolase recognition antibody regulated by the 2,4, 6-triaminopyrimidineAn agent;
(3) preparation of Fe-ZIF
Dissolving 2 g of 2-methylimidazole in 30 mL of anhydrous methanol, and marking as a solution A; in addition, 0.3 g of ferrous sulfate heptahydrate and 0.8 g of zinc nitrate hexahydrate are mixed and dissolved in 30 mL of anhydrous methanol and marked as solution B; mixing the two solutions, stirring uniformly, continuously stirring at 35 ℃ for reacting for 4 hours, centrifuging the mixed solution after the reaction is finished, collecting the obtained product, washing and centrifuging for 3 times by using anhydrous methanol, and drying the washed product in a vacuum drying oven at 60 ℃ overnight to obtain Fe-ZIF powder;
(4) preparation of copper sulfide quantum dots
Dissolving 30 mg of sodium sulfate nonahydrate in 3 mL of deionized water to obtain a sodium sulfide solution for later use, dissolving 80 mg of copper chloride and 90 mg of trisodium citrate in 300 mL of ultrapure water, magnetically stirring to obtain a light blue transparent solution, heating the fully dissolved solution, reacting for 30 min at 90 ℃, slowly dropwise adding the sodium sulfide solution in the heating process, wherein the solution gradually becomes dark green and precipitates are generated in the process, centrifuging the suspension after the reaction is finished, collecting the obtained product, washing and centrifuging for 3 times by using the ultrapure water, dissolving the washed copper sulfide quantum dot suspension in 5 mL of deionized water, and storing for later use at 4 ℃;
(5) preparation of Fe-ZIF loaded copper sulfide quantum dot composite material
Dissolving 80 mg of prepared Fe-ZIF powder in 300 mL of deionized water, carrying out magnetic stirring to fully dissolve and disperse the powder, then slowly dropwise adding the copper sulfide quantum dot suspension to fully load the copper sulfide quantum dots with the Fe-ZIF, stirring for 8 h, centrifuging the mixed solution, collecting the obtained product, washing and centrifuging for 3 times with the deionized water, and drying the washed product in a vacuum drying oven at 60 ℃ overnight to obtain the Fe-ZIF loaded copper sulfide quantum dot composite material;
(6) preparation of PBS buffer solution
11.94 g of disodium hydrogen phosphate dodecahydrate were taken out and dissolved in a 500 mL volumetric flask so as to be prepared into a solution having a concentration of 1/15 mol L-1As an aqueous solution of (a); taking 4.54 g of monopotassium phosphate, fixing the volume in a 500 mL volumetric flask and preparing into concentrated solutionDegree of 1/15 mol L-1As solution b; mixing the solution A and the solution B in proportion to prepare a series of PBS (phosphate buffer solution) with the pH value of 6.0-8.0;
(7) preparation of secondary antibody marker of Fe-ZIF loaded copper sulfide quantum dot combined with neuron specific enolase recognition antibody
mu.L of neuron-specific enolase secondary antibody (10. mu.g mL)-1) Added to 1 mL of 2 mg mL-1Carrying out oscillation incubation for 12 h at 4 ℃ in an aqueous solution of the Fe-ZIF-loaded copper sulfide quantum dot composite material, centrifuging, and dispersing the obtained product in 1 mL of PBS to obtain a secondary antibody marker solution of the Fe-ZIF-loaded copper sulfide quantum dot combined with a neuron-specific enolase recognition antibody;
(8) preparation of electrochemical immunosensor
1) Polishing a glassy carbon electrode with the diameter of 4 mm by using aluminum oxide polishing powder, cleaning by using ultrapure water, and polishing by using 6 mu L and 1.5 mg mL-1The primary-antibody marker solution of the graphite-like phase carbon nitride combined with neuron-specific enolase recognition antibody regulated and controlled by 2,4, 6-triaminopyrimidine is dripped on the surface of the electrode and dried at room temperature;
2) continuously dropwise adding bovine serum albumin solution with the mass fraction of 0.1% to the surface of the electrode, cleaning with ultrapure water, and airing at room temperature;
3) continuously dropwise adding 6 muL and 0.00005-100 ng mL-1A series of neuron specific enolase antigens with different concentrations are applied to the surface of the electrode, incubated for 2 hours, rinsed with ultrapure water and dried at room temperature;
4) and finally, dropwise adding 6 muL of Fe-ZIF loaded copper sulfide quantum dots and a second antibody marker solution combined with the neuron specific enolase recognition antibody, washing with ultrapure water, and airing at room temperature to obtain the electrochemical immunosensor for detecting the neuron specific enolase.
EXAMPLE 3 preparation of electrochemical immunosensor
(1) Preparation of graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine
Preparation of 2,4, 6-triaminopyrimidine-regulated graphite-like phase nitriding through copolymerization of melamine and 2,4, 6-triaminopyrimidineCarbon, 1 g of melamine and 50 mg of 2,4, 6-triaminopyrimidine were mixed thoroughly and homogeneously in an agate mortar for grinding, and the mixture was placed in a crucible with a lid and heated in a muffle furnace at 5 ℃ for 5 min-1Raising the temperature rising rate to 550 ℃, keeping heating for 4 h, and obtaining the graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine, wherein other conditions are the same when the 2,4, 6-triaminopyrimidine is not added, and the original graphite-like phase carbon nitride is prepared;
(2) preparation of primary anti-marker of graphite-like phase carbon nitride combined neuron-specific enolase recognition antibody regulated and controlled by 2,4, 6-triaminopyrimidine
20 microgram mL-1The primary antibody of the neuron-specific enolase is activated by using 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) at 4 ℃, and then is incubated with the graphite-like carbon nitride regulated by 2,4, 6-triaminopyrimidine for 6 hours at 4 ℃ to obtain a primary antibody marker of the graphite-like carbon nitride regulated by 2,4, 6-triaminopyrimidine and combined with the neuron-specific enolase recognition antibody;
(3) preparation of Fe-ZIF
Dissolving 3 g of 2-methylimidazole in 30 mL of anhydrous methanol, and marking as a solution A; in addition, 0.5 g of ferrous sulfate heptahydrate and 1 g of zinc nitrate hexahydrate are mixed and dissolved in 30 mL of anhydrous methanol, and the solution is marked as solution B; mixing the two solutions, stirring uniformly, continuously stirring at 35 ℃ for reacting for 4 hours, centrifuging the mixed solution after the reaction is finished, collecting the obtained product, washing and centrifuging for 3 times by using anhydrous methanol, and drying the washed product in a vacuum drying oven at 60 ℃ overnight to obtain Fe-ZIF powder;
(4) preparation of copper sulfide quantum dots
Dissolving 50 mg of sodium sulfate nonahydrate in 3 mL of deionized water to obtain a sodium sulfide solution for later use, dissolving 100 mg of copper chloride and 100 mg of trisodium citrate in 300 mL of ultrapure water, magnetically stirring to obtain a light blue transparent solution, heating the fully dissolved solution, reacting for 30 min at 90 ℃, slowly dropwise adding the sodium sulfide solution in the heating process, wherein the solution gradually becomes dark green and precipitates are generated in the process, centrifuging the suspension after the reaction is finished, collecting the obtained product, washing and centrifuging for 3 times by using the ultrapure water, dissolving the washed copper sulfide quantum dot suspension in 5 mL of deionized water, and storing for later use at 4 ℃;
(5) preparation of Fe-ZIF loaded copper sulfide quantum dot composite material
Dissolving 100 mg of prepared Fe-ZIF powder in 300 mL of deionized water, carrying out magnetic stirring to fully dissolve and disperse the powder, then slowly dropwise adding the copper sulfide quantum dot suspension to fully load the copper sulfide quantum dots with Fe-ZIF, stirring for 8 h, centrifuging the mixed solution, collecting the obtained product, washing and centrifuging for 3 times with deionized water, and drying the washed product in a vacuum drying oven at 60 ℃ overnight to obtain the Fe-ZIF loaded copper sulfide quantum dot composite material;
(6) preparation of PBS buffer solution
11.94 g of disodium hydrogen phosphate dodecahydrate were taken out and dissolved in a 500 mL volumetric flask so as to be prepared into a solution having a concentration of 1/15 mol L-1As an aqueous solution of (a); 4.54 g of monopotassium phosphate is taken and fixed to a 500 mL volumetric flask, and the volume is configured to be 1/15 mol L-1As solution b; mixing the solution A and the solution B in proportion to prepare a series of PBS (phosphate buffer solution) with the pH value of 6.0-8.0;
(7) preparation of secondary antibody marker of Fe-ZIF loaded copper sulfide quantum dot combined with neuron specific enolase recognition antibody
mu.L of neuron-specific enolase secondary antibody (10. mu.g mL)-1) Added to 1 mL of 3 mg mL-1Carrying out oscillation incubation for 12 h at 4 ℃ in an aqueous solution of the Fe-ZIF-loaded copper sulfide quantum dot composite material, centrifuging, and dispersing the obtained product in 1 mL of PBS to obtain a secondary antibody marker solution of the Fe-ZIF-loaded copper sulfide quantum dot combined with a neuron-specific enolase recognition antibody;
(8) preparation of electrochemical immunosensor
1) Polishing a glassy carbon electrode with the diameter of 4 mm by using aluminum oxide polishing powder, cleaning by using ultrapure water, and polishing by using 6 mu L and 2.5 mg mL-1The primary-antibody marker solution of the 2,4, 6-triaminopyrimidine-regulated graphite-phase carbon nitride-combined neuron-specific enolase recognition antibodyDropwise adding the solution to the surface of an electrode, and airing at room temperature;
2) continuously dropwise adding bovine serum albumin solution with the mass fraction of 0.1% to the surface of the electrode, cleaning with ultrapure water, and airing at room temperature;
3) continuously dropwise adding 6 muL and 0.00005-100 ng mL-1A series of neuron specific enolase antigens with different concentrations are applied to the surface of the electrode, incubated for 2 hours, rinsed with ultrapure water and dried at room temperature;
4) and finally, dropwise adding 6 muL of Fe-ZIF loaded copper sulfide quantum dots and a second antibody marker solution combined with the neuron specific enolase recognition antibody, washing with ultrapure water, and airing at room temperature to obtain the electrochemical immunosensor for detecting the neuron specific enolase.
Example 4 detection of neuron-specific enolase
(1) Ag/AgCl is used as a reference electrode, a platinum wire is used as a counter electrode, the prepared electrochemical luminescence sensor is used as a working electrode and is correctly connected in a cassette of a chemiluminescence detector, an electrochemical workstation and the chemiluminescence detector are connected together, the high voltage of a photomultiplier is set to be 500V, and the electrochemical luminescence sensor contains 20 mmoL L-1The test was performed in potassium persulfate in PBS buffer;
(2) detecting the neuron specific enolase standard solution by an electrochemical luminescence method, wherein the voltage test range is-1.6-0V;
(3) and observing the electrochemiluminescence intensity of the sensor before and after the addition of the neuron-specific enolase, recording the linear relation between the electrochemiluminescence intensity value and the concentration of the neuron-specific enolase, and drawing a working curve.
Example 5 detection of neuron-specific Enolase
(1) Ag/AgCl is used as a reference electrode, a platinum wire is used as a counter electrode, the prepared electrochemical luminescence sensor is used as a working electrode and is correctly connected in a cassette of a chemiluminescence detector, an electrochemical workstation and the chemiluminescence detector are connected together, the high voltage of a photomultiplier is set to be 600V, and the electrochemical luminescence sensor contains 50 mmoL L-1The test was performed in potassium persulfate in PBS buffer;
(2) detecting the neuron specific enolase standard solution by an electrochemical luminescence method, wherein the voltage test range is-1.5-0V;
(3) and observing the electrochemiluminescence intensity of the sensor before and after the addition of the neuron-specific enolase, recording the linear relation between the electrochemiluminescence intensity value and the concentration of the neuron-specific enolase, and drawing a working curve.
Example 6 detection of neuron-specific enolase
(1) Ag/AgCl is used as a reference electrode, a platinum wire is used as a counter electrode, the prepared electrochemical luminescence sensor is used as a working electrode and is correctly connected in a cassette of a chemiluminescence detector, an electrochemical workstation and the chemiluminescence detector are connected together, the high voltage of a photomultiplier is set to be 700V, and the electrochemical luminescence sensor contains 80 mmoL L-1The test was performed in potassium persulfate in PBS buffer;
(2) detecting the neuron specific enolase standard solution by an electrochemical luminescence method, wherein the voltage test range is-1.4-0V;
(3) and observing the electrochemiluminescence intensity of the sensor before and after the addition of the neuron-specific enolase, recording the linear relation between the electrochemiluminescence intensity value and the concentration of the neuron-specific enolase, and drawing a working curve.
Example 7 detection of neuron-specific enolase
(1) Ag/AgCl is used as a reference electrode, a platinum wire is used as a counter electrode, the prepared electrochemical luminescence sensor is used as a working electrode and is correctly connected in a cassette of a chemiluminescence detector, an electrochemical workstation and the chemiluminescence detector are connected together, the high voltage of a photomultiplier is set to be 800V, and the electrochemical luminescence sensor contains 100 mmoL L-1The test was performed in potassium persulfate in PBS buffer;
(2) detecting the neuron specific enolase standard solution by an electrochemical luminescence method, wherein the voltage test range is-1.3-0V;
(3) and observing the electrochemiluminescence intensity of the sensor before and after the addition of the neuron-specific enolase, recording the linear relation between the electrochemiluminescence intensity value and the concentration of the neuron-specific enolase, and drawing a working curve.
Claims (1)
1. A preparation method of an electrochemical immunosensor based on 2,4, 6-triaminopyrimidine-regulated graphite-like-phase carbon nitride is characterized by comprising the following steps:
(1) preparation of graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine
Preparing graphite-like carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine by copolymerizing melamine and 2,4, 6-triaminopyrimidine, fully and uniformly mixing 1 g of melamine and 10-50 mg of 2,4, 6-triaminopyrimidine in an agate mortar for grinding, then placing the mixture in a crucible with a cover, and placing the crucible in a muffle furnace for 5 ℃ for min-1Raising the temperature rising rate to 550 ℃, keeping heating for 4 h, and obtaining the graphite-like phase carbon nitride regulated and controlled by 2,4, 6-triaminopyrimidine, wherein other conditions are the same when the 2,4, 6-triaminopyrimidine is not added, and the original graphite-like phase carbon nitride is prepared;
(2) preparation of primary anti-marker of graphite-like phase carbon nitride combined neuron-specific enolase recognition antibody regulated and controlled by 2,4, 6-triaminopyrimidine
5-20 microgram mL-1The primary antibody of the neuron-specific enolase is activated by using 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) at 4 ℃, and then is incubated with the graphite-like carbon nitride regulated by 2,4, 6-triaminopyrimidine for 6 hours at 4 ℃ to obtain a primary antibody marker of the graphite-like carbon nitride regulated by 2,4, 6-triaminopyrimidine and combined with the neuron-specific enolase recognition antibody;
(3) preparation of Fe-ZIF
Firstly, dissolving 1-3 g of 2-methylimidazole in 30 mL of anhydrous methanol, and marking as a solution A; in addition, 0.1-0.5 g of ferrous sulfate heptahydrate and 0.6-1 g of zinc nitrate hexahydrate are mixed and dissolved in 30 mL of anhydrous methanol and marked as solution B; mixing the two solutions, stirring uniformly, continuously stirring at 35 ℃ for reacting for 4 hours, centrifuging the mixed solution after the reaction is finished, collecting the obtained product, washing and centrifuging for 3 times by using anhydrous methanol, and drying the washed product in a vacuum drying oven at 60 ℃ overnight to obtain Fe-ZIF powder;
(4) preparation of copper sulfide quantum dots
Dissolving 20-50 mg of sodium sulfate nonahydrate in 3 mL of deionized water to obtain a sodium sulfide solution for later use, dissolving 50-100 mg of copper chloride and 80-100 mg of trisodium citrate in 300 mL of ultrapure water, magnetically stirring to obtain a light blue transparent solution, heating the fully dissolved solution, reacting for 30 min at 90 ℃, slowly dropwise adding the sodium sulfide solution in the heating process, observing that the solution gradually becomes dark green and precipitates are generated in the process, centrifuging the suspension after the reaction is finished, collecting the obtained product, washing and centrifuging for 3 times by using the ultrapure water, dissolving the washed copper sulfide quantum dot suspension in 5 mL of deionized water, and storing for later use at 4 ℃;
(5) preparation of Fe-ZIF loaded copper sulfide quantum dot composite material
Dissolving 50-100 mg of prepared Fe-ZIF powder in 300 mL of deionized water, performing magnetic stirring to fully disperse the powder, then slowly dropwise adding the copper sulfide quantum dot suspension to fully load the copper sulfide quantum dots with Fe-ZIF, stirring for 8 hours, centrifuging the mixed solution, collecting the obtained product, washing and centrifuging for 3 times with deionized water, and drying the washed product in a vacuum drying oven at 60 ℃ overnight to obtain the Fe-ZIF loaded copper sulfide quantum dot composite material;
(6) preparation of PBS buffer solution
11.94 g of disodium hydrogen phosphate dodecahydrate were taken out and dissolved in a 500 mL volumetric flask so as to be prepared into a solution having a concentration of 1/15 mol L-1As an aqueous solution of (a); 4.54 g of monopotassium phosphate is taken and fixed to a 500 mL volumetric flask, and the volume is configured to be 1/15 mol L-1As solution b; mixing the solution A and the solution B in proportion to prepare a series of PBS (phosphate buffer solution) with the pH value of 6.0-8.0;
(7) preparation of secondary antibody marker of Fe-ZIF loaded copper sulfide quantum dot combined with neuron specific enolase recognition antibody
20-100 μ L of neuron-specific enolase secondary antibody (10 μ g mL)-1) Adding 1 mL to 1-3 mg mL-1Fe-ZIF negativeCarrying out oscillation incubation for 12 h at 4 ℃ in the copper sulfide quantum dot-loaded composite material aqueous solution, centrifuging, and dispersing the obtained product in 1 mL of PBS to obtain a secondary antibody marker solution of Fe-ZIF-loaded copper sulfide quantum dots and combined with a neuron-specific enolase recognition antibody;
(8) preparation of electrochemical immunosensor
1) Polishing a glassy carbon electrode with the diameter of 4 mm by using aluminum oxide polishing powder, cleaning by using ultrapure water, and then polishing 6 muL and 0.5-2.5 mg mL-1The primary-antibody marker solution of the graphite-like phase carbon nitride combined with neuron-specific enolase recognition antibody regulated and controlled by 2,4, 6-triaminopyrimidine is dripped on the surface of the electrode and dried at room temperature;
2) continuously dropwise adding bovine serum albumin solution with the mass fraction of 0.1% to the surface of the electrode, cleaning with ultrapure water, and airing at room temperature;
3) continuously dropwise adding 6 muL and 0.00005-100 ng mL-1A series of neuron specific enolase antigens with different concentrations are applied to the surface of the electrode, incubated for 2 hours, rinsed with ultrapure water and dried at room temperature;
4) and finally, dropwise adding 6 muL of Fe-ZIF loaded copper sulfide quantum dots and a second antibody marker solution combined with the neuron specific enolase recognition antibody, washing with ultrapure water, and airing at room temperature to obtain the electrochemical immunosensor for detecting the neuron specific enolase.
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| CN114609218A (en) * | 2022-05-01 | 2022-06-10 | 济南大学 | A kind of preparation method of photoelectrochemical immunosensor for detecting neuron-specific enolase |
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2021
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114609218A (en) * | 2022-05-01 | 2022-06-10 | 济南大学 | A kind of preparation method of photoelectrochemical immunosensor for detecting neuron-specific enolase |
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