Electrochemical sensor of DNA (deoxyribonucleic acid) probe based on fluorescein and sulfydryl modification

A technology of DNA probe and sulfhydryl modification, which is applied in the field of electrochemical sensors of DNA probes, and can solve the problems of probe DNA conformation change and complexity

Inactive Publication Date: 2014-04-02
邢士超
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the conformational changes of some probe DNA are very complicated, and for some simple sensors, their sensitivity and s...

Method used

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  • Electrochemical sensor of DNA (deoxyribonucleic acid) probe based on fluorescein and sulfydryl modification
  • Electrochemical sensor of DNA (deoxyribonucleic acid) probe based on fluorescein and sulfydryl modification
  • Electrochemical sensor of DNA (deoxyribonucleic acid) probe based on fluorescein and sulfydryl modification

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] An electrochemical sensor based on fluorescein and thiol-modified DNA probes, including electrodes and DNA probes, the electrodes adopt a three-electrode system, wherein the gold electrode is the working electrode, the calomel electrode is the reference electrode, and the platinum wire is the Counter electrode; the two ends of the DNA probe are respectively modified with fluorescein and mercapto; gold nanoparticles are deposited on the surface of the gold electrode; gold-sulfur is passed between the mercapto group modified on the DNA probe and the gold nanoparticles Bonding; the gold nanoparticles and the fluorescein modified on the DNA probe are adsorbed on the surface, making the DNA probe form an arched structure.

[0024] A kind of electrochemical sensor based on fluorescein and thiol-modified DNA probe as above, the specific method of gold electrode and DNA probe assembly is as follows:

[0025] 1) Clean the surface of the gold electrode with a cleaning agent, then...

Embodiment 2

[0029] The formation process of gold nanoparticles on gold electrodes was characterized by SEM. The size and quantity of electrodeposited gold nanoparticles can be controlled by controlling the deposition voltage, solution concentration and deposition time. Figure 1-4 SEM of bare gold electrode and gold nanoparticle modified gold electrode surface. like figure 1 As shown, the surface of the bare gold electrode is basically smooth, and there are no nanoparticles on the surface; when the voltage is low and the concentration of chloroauric acid is relatively dilute, the electrodeposition speed is slow, and after 180s of deposition, there are only some small particles on the surface of the gold electrode, such as figure 2 Shown; at 6mmol L -1 In chloroauric acid solution, after deposition of -400mV (vs.SCE) for 300s, it can be seen that the surface of the gold electrode is covered with a large number of gold nanoparticles, and there are many gaps between these gold nanoparticl...

Embodiment 3

[0032] Select the following sequence as the probe, 5'-T6 -TAG GAA ACA CCA AAG ATG ATA TTT-T 6 -3', respectively modify the two ends of the probe sequence with fluorescein and thiol, the sequence is as follows:

[0033] ssDNA-A:

[0034] 5'-F-T 6 -TAG GAA ACA CCA AAG ATG ATA TTT-T 6 -SH-3', wherein F represents fluorescein.

[0035] ssDNA-B:

[0036] 5'-AAA TAT CAT CTT TGG TGT TTC CTA-3'(Target DNA)

[0037] ssDNA-C:

[0038] 5'-TAC GAG TTG AGA GCA AGC AGA GTT-3'(non-complementary DNA)

[0039] ssDNA-D:

[0040] 5'-AAA TAT CAT CTT TTG TGT TTC CTA-3' (single base mismatch DNA)

[0041] The above artificial sequences were provided by Beijing Saibaisheng Co., Ltd.

[0042] Using the method of Example 1, the ssDNA-A sequence was modified on the bare gold electrode and the nano-gold modified electrode, respectively, and then the modified electrodes were respectively inserted into the PBS buffer solution containing the target DNA, hybridized at room temperature for 1 h, and ...

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Abstract

The invention discloses an electrochemical sensor of a DNA probe based on fluorescein and sulfydryl modification. The electrochemical sensor comprises an electrode and a DNA probe, wherein the electrode adopts a three-electrode system, and the two ends of the DNA probe are respectively modified with the fluorescein and the sulfydryl; gold nanoparticles are deposited on the surface of a gold electrode, and the sulfydryl modified on the DNA probe is combined with the gold nanoparticles through a gold-sulfur bond; the gold nanoparticles and the fluorescein modified on the DNA probe can enable the DNA probe to form an arch-shaped structure through the surface adsorption action. The electrochemical sensor provided by the invention has the advantages that the gold nanoparticles are modified on the surface of the gold electrode through an electro-deposition effect, the nanogold modification can greatly increase the fixed carrying capacity of probe ssDNA of the surface of the electrode, and the probe forms the arch-shaped structure through the surface adsorption action of the nanogold on the fluorescein. The connection has high electron transmission efficiency, the change of the DPV signal before and after hybridization can be improved, and the detection sensitivity is improved.

Description

technical field [0001] The invention relates to the technical field of electrochemical biosensors, in particular to an electrochemical sensor based on fluorescein and thiol-modified DNA probes. Background technique [0002] Recently, many electrochemical DNA (E-DNA) sensors and similar aptamer-based electrochemical (E-AB) sensors have emerged in large numbers. DNA sensor. Wherein the probe DNA can be linear or circular DNA. Probe DNA is generally modified with a sulfhydryl group at one end and a redox label at the other end. Self-assembled to the surface of gold electrodes through the action of gold-sulfur bonds. After hybridization with the target DNA, the configuration of the probe DNA is changed, so that the electron transfer efficiency between the redox marker and the electrode surface is changed, thereby changing the electrical signal, indicating hybridization. This simple sensor is widely used in the research of DNA, enzymes, metal ions and small organic molecules....

Claims

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Application Information

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IPC IPC(8): G01N27/26G01N27/30G01N27/327
Inventor 邢士超张少燕陈颖蒋钢苗志敏刘云国杨钊苏浩然
Owner 邢士超
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