硒化铅纳米粒子DNA电化学传感器检测花椰菜花叶病毒35S启动子基因序列

DNA Electrochemical Sensor Based on PbSe Nanoparticle for the Sensitive Detection of CaMV35S Transgene Gene Sequence

以水热法合成十六烷基三甲基溴化铵(CTAB)修饰的PbSe纳米粒子。在碳糊电极表面制备的PbSe纳米粒子壳聚糖(CHIT)复合膜上,实现了DNA的固定和杂交,并用循环伏安法和电化学交流阻抗法进行了表征。应用电活性分子亚甲紫(MV)作为杂交指示剂,以微分脉冲伏安法对转基因植物CaMV35S启动子基因片段进行测定,检测范围为5.0×10-11～5.0×10-6mol/L;检出限为1.6×10-11mol/L(3σ)。该传感器能很好地识别DNA互补序列、非互补序列和2碱基错配序列。

PbSe nanoparticle surface-modified with cetyltrimethylammonium bromide（CTAB） was synthesized with a hydrothermal route.PbSe nanoparticle/chitosan（CHIT） composite films were prepared on the carbon paste electrode（CPE） and characterized by SEM and electrochemical methods.The immobilization and hybridization of DNA on the composite films were investigated by electrochemical impedance spectroscopy and cyclic voltammetry.PbSe nanoparticle/CHIT composite matrix has some advantages,such as large ratio surface area,good biocompatibility and good film-forming ability,and can markedly enhance the immobilization amount of DNA.Differential pulse voltammetry was used to the sensitive detection of the hybridization of DNA with methylene violet（MV） as the indicator.This DNA electrochemical sensor can differentiate the completely complementary DNA sequence and the 2-base mismatched DNA sequence,indicating a good selectivity.The specific sequence related to CaMV35S promoter gene in some transgenic plants was satisfactorily detected using this DNA electrochemical sensor with a linear range of 5.0×10^-11-5.0×10^-6 mol/L,and a detection limit of 1.6×10^-11 mol/L.