基于纳米TiO2和金纳米星的光电化学适配体传感器检测Hg2+的研究

Detection of Hg2+ by TiO2 Nanoparticles and Au Nanostars Based Photoelectrochemical Aptamer Biosensor

构建了一种适配体修饰的Hg^2+传感器,以氧化铟锡(ITO)导电玻璃为基底电极,纳米TiO2为光电活性材料,通过金纳米星固定特异性识别单元巯基修饰适配体。当适配体特异性识别Hg^2+时,适配体富碱基T序列与Hg^2+结合形成折叠的发卡结构,传感器界面发生改变从而实现Hg^2+定量分析。采用时间-电流法、交流阻抗法等电化学方法对所构建的传感器检测性能进行研究。实验结果表明,在优化实验条件下,该方法用于检测Hg^2+的线性范围为1.0×10^-9~5.0×10^-7 mol/L,检测限为3.1×10^-10 mol/L。该传感器制备过程简单,具有较高的检测灵敏度,较高的稳定性和可重复性。

A photoelectrochemical method was developed for Hg^2+ detection using TiO2 nanoparticles as photoactive material,Au nanostars as immobilization substrate and-SH modified aptamer as recognition element.In the presence of Hg^2+,DNA aptamer could fold into a hairpin structure with"T-Hg^2+-T"recognition for quantitative analysis of Hg^2+.The performance of aptasensor was studied by electrochemical methods such as current-time curve and electrochemical impedance spectroscopy.Under optimal conditions,the aptasensor showed linear range for Hg^2+ detection from 1.0×10^-9 to 5.0×10^-7 mol/L and a detection limit of 3.1×10^-10 mol/L(3σ).The aptamer sensor is easy in preparation,highly sensitive,stable and repeatable.