基于四氧化三钴-石墨烯纳米复合材料的电化学DNA传感器

Construction of Electrochemical DNA Sensor with Co_3O_4-graphene Nanocomposite Modified Electrode

以离子液体碳糊电极(CILE)为基底电极,四氧化三钴-石墨烯(Co_3O_4-GR)纳米复合材料为修饰剂制备了一种新型电化学DNA传感器,并应用于副溶血弧菌tlh特征序列测定.利用壳聚糖(CTS)将Co_3O_4-GR复合材料固定在CILE表面,然后将探针ssDNA序列通过吸附法固定在CTS/Co_3O_4-GR/CILE上,与目标ssDNA序列发生特异性的分子杂交反应,以铁氰化钾为电化学信号分子,根据杂交反应前后伏安信号的差异实现了对目标ssDNA检测的目的,建立相应的工作曲线,求解线性范围和检测限等分析参数.由于复合材料具有大的比表面积故能够增加探针ssDNA的负载量,其高导电性有效地提高电化学响应信号.在最佳实验条件下使用差分脉冲伏安法可对1.0×10^(-14)~1.0×10^(-6)mol/L浓度范围的目标ssDNA序列进行检测,检测限为3.3×10^(-15)mol/L(3σ),该DNA传感器可有效识别单碱基和三碱基错配序列,具有良好的应用前景.

A new electrochemical DNA sensor for the determination of target tlh sequence was constructed with Co_3O_4-graphene( GR) modified carbon ionic liquid electrode( CILE). Single-stranded DNA( ss DNA) probe was immobilized on the surface of CTS/Co_3O_4-GR/CILE,which could hybridize with the target ss DNA sequence. By using potassium ferricyanide as the probe,electrochemical response could be monitored with the differences of hybridization reaction. The presence of Co_3O_4-GR nanocomposite could increase the adsorption amount of probe ss DNA sequence with increased conductivity. Under the optimal conditions,differential pulse voltammetry was used to monitor the DNA hybridization,and the changes of peak current were in linear with the target ss DNA concentration in the range from 1. 0 × 10^(-14) to 1. 0 × 10^(-6) mol/L with a detection limit of 3. 3 × 10^(-15) mol/L. The proposed DNA sensor could successfully distinguish single fromthree mismatched ss DNA sequence,which showed the great potential applications.