基于金-普鲁士蓝复合纳米粒子的电流型DNA传感器的制备

在玻碳电极(GCE)表面依次电聚合硫堇膜(PTh)、电沉积金-普鲁士蓝复合纳米粒子(PB-Au)和金纳米粒子(GN)，利用GN比表面积大和生物相容性好的特性，进而固定单链DNA(ssDNA)，制备一种电流型DNA传感器(GCE/PTh/PB-Au/GN/ssDNA).利用电化学交流阻抗技术(EIS)和循环伏安法(CV)对电极的修饰过程进行表征，以亚甲基蓝(MB)为杂交指示剂，利用微分脉冲伏安法(DPV)对DNA进行检测.结果表明，所制备的DNA传感器可以对DNA进行灵敏检测，在1.0×10^-14~1.0×10^-6 mg/L范围内，DPV的峰电流与DNA质量浓度呈良好线性关系，工作曲线斜率为-13.4 μA/decade，相关系数为0.994，检测下限为1.0×10^-14 mg/L.所制备的传感器灵敏准确，不仅可用于基因检测，而且对重金属离子及其他有机污染物的检测也有重要研究价值.

Preparation of Electrochemical DNA Sensors Based on PB-Au Nanocomposites

Thionine was firstly electropolymerized on the glassy carbon electrode (GCD) surface,and then prussian blue-gold nanocomposites (PB-Au) and gold nanoparticals (GN) were electrodeposited on modified electrode surface respectively.Finally,DNA probes (ssDNA) were conjugated with GN through Au-NH2 bond,and a DNA biosensor (GCE/PTh/PB-Au/GN/ssDNA) was prepared.The preparation processes of DNA biosensors were characterized by electrochemical impedance spectroscopy (EIS),cyclic voltammetry (CV) and differential pulse voltammetry (DPV).The DNA was detected with the sensor by differential pulse voltammetry (DPV) using methylene blue (MB) as hybridization indicator.The results exhibited linear response (r=0.994) to DNA and slope of curve (-13.4 μA/decade) in the concentration range from 1.0×10^-14~1.0×10^-6 mg/L with a lower detection limit of 1.0×10-14 mg/L.The sensor prepared is sensitive and accurate which makes it applicable not only for gene detection but also for detection of heavy metal ion and organic pollutant.