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Electrochemical biosensor modified by graphene quantum dot and preparation method thereof

A technology of graphene quantum dots and biosensors, applied in the direction of material electrochemical variables, scientific instruments, instruments, etc., can solve the problems of DNA biosensors that have not been reported, and achieve the effect of broad application prospects

Inactive Publication Date: 2010-09-29
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These properties make it have great application prospects in the field of biosensors. Many articles have been published on electrochemical biosensors using graphene as a membrane material, but DNA biosensors targeting graphene quantum dots have not been reported yet.

Method used

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  • Electrochemical biosensor modified by graphene quantum dot and preparation method thereof
  • Electrochemical biosensor modified by graphene quantum dot and preparation method thereof
  • Electrochemical biosensor modified by graphene quantum dot and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Example 1: Modification of glassy carbon electrode

[0020] The glassy carbon electrode was first polished on coarse corundum sandpaper (400 mesh), then on fine corundum sandpaper (1000 mesh), and finally on silk containing alumina (particle size 0.05 μm) mortar, and then ethanol, Water was ultrasonically cleaned for 5 minutes respectively to obtain a bare glassy carbon electrode with a clean surface. The concentration is 15mg L -1 10 μL of the graphene quantum dot aqueous solution was added dropwise to the surface of the treated electrode. In the first two hours, the electrode surface was covered with an Eppendorf tube to allow the solution to slowly evaporate to form a uniform covering layer, and then naturally After drying, the graphene quantum dot-modified glassy carbon electrode is obtained, which is stored in a refrigerator at 4°C for later use.

[0021] Graphene oxide used in the present invention is synthesized by graphite powder according to the Hemmers metho...

Embodiment 2

[0022] Example 2: Electron transfer of graphene quantum dots on the electrode surface

[0023] The bare glassy carbon electrode with clean surface treatment and the glassy carbon electrode modified by graphene quantum dots prepared by the present invention were respectively measured on the CHI660c electrochemical workstation in terms of their K-containing 3 [Fe(CN) 6 ] / K 4 [Fe(CN) 6 ] The magnitude of the cyclic voltammetry signal in the electrolytic buffer of the probe. For experimental results, see figure 1 , the electrical signal of the electrode modified by graphene quantum dots is significantly larger than that of the bare glassy carbon electrode. It can be seen that graphene quantum dots are indeed an ideal electrode surface film material.

Embodiment 3

[0024] Example 3: Effects of Different pH Values ​​of Solutions on Electrochemical Signals

[0025] Using the differential voltammetry pulse method, the glassy carbon electrodes modified by graphene quantum dots were respectively immersed in the buffer solution (10mM Tris-HCl, 1mM EDTA, 0.1M NaCl, pH 4-9) containing single-stranded DNA or double-stranded DNA. For 1 hour each, electrical signals were measured. The single-stranded DNA 1 strand sequence: 5'-TCT CTC AGT CCG TGG TAG GGC AGG TTG GGG TGA CT-3', the 2nd strand is the complementary sequence of 1st strand: 5'-AG TCA CCC CAA CCT GCC CTA CCA CGG ACT GAG AGA -3'. See results figure 2 , when the pH value of the solution is 4 or 5, there is little difference in the electrical signal, and when the pH value is 6, the electrical signal increases greatly, and the electrical signal decreases significantly from pH 7 to pH 9. It can be seen that graphene quantum dots are at pH 6 of the solution The modified electrode can obtain...

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Abstract

The invention relates to an electrochemical biosensor modified by graphene quantum dots and a preparation method thereof. The electrochemical biosensor is a three-electrode system sensor; in a three-electrode, the counter electrode is a platinum electrode, a reference electrode is a saturated calomel electrode, and a working electrode is a glassy carbon electrode the surface of which is coated with 1-4 layers of the graphene quantum dots. The electrochemical biosensor modified by the graphene quantum dots can successfully recognize an objective single-stranded DNA with the lowest concentration of 50nm; in case of the objective single-stranded DNA, equivalent and complementary single-stranded DNA and the objective single-stranded DNA form a double-stranded DNA; an electrochemical signal and the complementary single-stranded DNA have obvious differences so as to make effects on rapidly detecting the objective single-stranded DNA; and the single-stranded DNA section does not need to be modified by sulfydryl or a fluorescence group, thus achieving convenient application. In the invention, the detected single-stranded DNA is nucleic acid of an arbitrary sequence section; and theoretically the invention is applicable to an arbitrary single-stranded nucleic acid sequence which can not form an internal double-strand, thus the single-stranded nucleic acid sequence is displaced into a specific sequential gene related to diseases, i.e. the invention can be used in gene detection related to diseases, thus having wide application prospect.

Description

technical field [0001] The invention relates to an electrochemical biosensor and a preparation method thereof, in particular to an electrochemical biosensor modified with graphene quantum dots and a preparation method thereof. Background of the invention [0002] DNA is the basic genetic material of all organisms, and its detection plays a vital role in the fields of medical diagnosis, bioengineering and environmental protection. As a new detection method, DNA electrochemical biosensor needs simple instruments, fast and sensitive detection, so it develops rapidly, and a large number of literatures have been reported so far. [0003] Electrochemical biosensors are a type of biosensors that use electrodes as signal converters to measure potential or current. The electrochemical system realizes the input or output of electrical energy by means of electrodes, so as to obtain the electrical signal of the modified substance on the electrode surface, and a three-electrode system i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/26G01N27/327
Inventor 李根喜陈桂芳李婷刘月星陈震宇陈琳
Owner SHANGHAI UNIV
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