基于电化学还原氧化石墨烯的电化学DNA生物传感器

Electrochemical DNA biosensors based on electrochemical reduced graphene oxide

使用还原氧化石墨烯(rGO)制备一种简单、快速和可重复方法构建DNA生物传感器。将带负电的氧化石墨烯(GO)与半胱氨酸上带正电的氨基基团通过静电作用相互吸附,用线性扫描伏安法(LSV)电化学还原电极表面吸附的GO。将二茂铁标记的DNA(Fc-DNA)探针固定到r GO表面,成功构建DNA传感器。传感器的制备过程使用循环伏安法和拉曼光谱表征。通过杂化前后DNA传感器所展现出方波信号峰电流的差异,实现对目标DNA的定量检测。实验结果表明:目标DNA浓度在1. 0×10^(-13)～1. 0×10^(-6)mol/L范围内,峰电流变化与目标DNA浓度呈线性关系,线性相关系数为0. 981,检测限是2. 0×10^(-13)mol/L (S/N=3)。

A simple,facile and reproducible approach is used for fabrication of DNA biosensors based on reduced graphene oxide(r GO).The graphene oxide(GO)nanosheets are assembled onto cysteamine-modified gold electrodes via electrostatic interaction between the positively charged amino group of cysteamine and the negatively charged groups present in GO,followed by electro-reduction through linear sweep voltammetry(LSV)and functionalization with ferrocene-labeled DNA probe.The stepwise assembly of the DNA(Fc-DNA)biosensor is characterized with cyclic voltammetry and Raman spectroscopy.The target DNA can be quantitatively detected based on the variation of square wave voltammetry(SWV)signal of the biosensor before and after hybridization with target DNA.The peak current variation has a linear relationship with the target DNA concentration in the range of 1.0×10-13~1.0×10-6 M,with linearly dependent coefficient of 0.981 and the detection limit(LOD)is 2.0×10-13 mol/L(S/N=3).