基于Au@Ag核壳纳米材料的信号增强型电化学适配体传感器测定水体中Hg^(2+)

Signal enhanced electrochemical aptasensor for detection of Hg^(2+) based on Au@Ag core-shell nanomaterial

利用种子生长法合成Au@Ag核壳材料,并用透射电镜、紫外可见光谱对其进行表征,以其作为分子信标构建电化学适配体传感器,用以分析检测水体中的Hg^(2+)。通过T-Hg^(2+)-T化学结合作用,在电极表面聚集多个Au@Ag单元进行信号放大,实现对Hg^(2+)的高灵敏检测。在最优实验条件下,示差脉冲伏安法(DPV)实验结果表明,电流响应随Hg^(2+)浓度的增加而增加,并在0.5~50 nmol/L的范围内呈现良好线性相关性,该传感器对Hg^(2+)的检出限低至0.03 nmol/L。将此方法应用于检测实际水体中的Hg^(2+),其加标回收率为91.6%~110.3%。

Au @ Ag core-shell nanostructure owns higher catalytic activity than alloy or monometal nanoparticles due to synergistic effect between Au and Ag. In this study, Au @ Ag core-shell nanomaterials were synthesized by seed-mediated growth method, which were characterized by transmission electron microscope （TEM） and UV-Vis spectrometry （UV-vis）. The novel electrochemical aptasensor was constructed by using Au@ Ag core-shell nanomaterial as label for detection of Hg^2＋ in water sample. Meanwhile, the electrochemical signal was amplified by aggregating Au@ Ag labels on the surface of electrode based on T-Hg2~ -T, which achieved a sensitive detection of Hg^2＋. Under optimal conditions, the sensor presented good electrochemical responses to Hg2. concentration. The result of pulse voltammetry （DPV） showed the current responses increased with the increasing of Hg^2＋ concentration, which exhibited linear in the range of 0. 5 -50 nmol/L with a detection limit of 0. 03 nmol/L. More importantly, this developed biosensor could be applied in detecting Hg^2＋ in real water sample, and the recoveries of standard addition in water varied from 91.6 % ~ 110. 3 %.