基于纳米MnO_2的免标记型DNA电化学生物传感器用于大肠杆菌的测定  

Lable-free Detection of Escherichia Coli Based on Nano-MnO_2 Modified DNA Electrochemical Biosensor

作　　者：刘志敏[1] 李哲建[1] 康宁[1] 

机构地区：[1]河南工业大学化学化工学院,河南郑州450052

出　　处：《分析测试学报》2008年第12期1269-1272,1277,共5页Journal of Instrumental Analysis

基　　金：河南省教育厅自然科学研究资助项目(2008B150006);河南工业大学博士基金资助项目(150196)

摘　　要：以室温固相合成法制备纳米MnO2,通过壳聚糖（CHIT）的成膜效应将纳米MnO2固定在玻碳电极表面。DNA在MnO2/CHIT膜上的固定和杂交通过循环伏安和电化学交流阻抗进行表征。以电化学阻抗免标记法检测目标DNA,固定于电极表面的DNA探针与目标DNA杂交后使电极表面的电子传递电阻增大,以此作为检测信号可以高灵敏度地测定目标DNA。电化学阻抗谱检测大肠杆菌基因片段的线性范围为2.0×10^-11 ～2.0×10^-6mol/L,检出限为1.0×10^-12mol/L。MnO2 nanopartiele was synthesized by solid state reaction at room temperature and was immobilized on glass carbon electrode via the film forming property of chitosan（CHIT）. The immobilization and hybridization of DNA on the MnO2/CHIT film were characterized by cyclic vohammetry（CV） and electrochemical impedance spectroscopy （EIS） method. The results indicated that the electron transfer resistance （Ret） of the electron surface was increased after the hybridization of probe DNA with target DNA. Based on this, a sensitive label-free DNA electrochemical biosensor was fabricated. Under optimal conditions, the DNA biosensor showed a wide linear response to the logarithm values of Escherichia coli concentration in the range of 2.0 × 10^-11 -2.0 × 10^-6 mol/L, with a detection limit of 1.0 × 10^-12 mol/L.

关 键 词：纳米MNO2 DNA 电化学交流阻抗 大肠杆菌 测定 

分 类 号：O657.1[理学—分析化学] R378.21[理学—化学]