基于PbS量子点和金纳米颗粒的可卡因适体传感器的研究

Preparation of cocaine aptamer sensor based on PbS quantum dots and Au nanoparticles

本文采用水热法合成了硫化铅量子点,将其与壳聚糖混合后修饰在玻碳电极上,利用PbS与巯基之间的强烈的键和作用,直接将所合成的带巯基的与可卡因适体互补的DNA固定到电极上,将金纳米颗粒标记在可卡因适体作为示踪物检测可卡因,研制了一种新型的用于快速测定可卡因的适体传感器。该适体传感器与不同浓度的可卡因培育时,可卡因适体与可卡因发生特异性结合,致使可卡因适体从电极上脱离下来。随着可卡因浓度的增加,脱落的金纳米颗粒的量增加,其催化H2O2的电流减少,实现对可卡因的检测。考察了适体传感器的电化学特性,同时也研究了测试液pH值、培育时间等实验条件对传感器性能的影响。通过扫描电镜观察了量子点的形貌。该传感器在可卡因浓度为1.0～100 nmol.dm-3的范围内有良好的线性关系,检测下限为0.3 nmol.dm-3。实验结果表明,该适体传感器响应迅速,灵敏度高,具有良好的重现性和稳定性。

A novel cocaine aptamer sensor for rapid determination of cocaine in human serum has been developed.The PbS quantum dots were prepared by solvothermal reaction.The aptamer sensor was prepared by immobilizing thiolated complementary DNA onto the surface of glassy carbon electrode modified with PbS quantum dots and chitosan film via the strong bound between PbS and-SH group.Au nanoparticles-labeled cocaine aptamer was used as tracer to detect cocaine.When the aptamer sensor was incubated with cocaine,the specify bound occurred between cocaine and its aptamer,resulting in Au nanoparticles-labeled cocaine aptamer dropping off from the electrode.Then,the reduction current of H2O2 catalyzed by Au NPs decreased,which is proportion to the concentration of cocaine.The electrochemical behavior of aptamer sensor was studied.Other experimental conditions such as pH,incubation time of cocaine aptamer were studied too.The prepared aptamer sensor offered an amperometric response for cocaine ranging from 1.0 to 100.0 nmol·dm-3 with a detection limit of 0.3 nmol·dm-3.The result showed that the aptamer sensor displayed rapid response,high sensitivity,good repeatability and long-term stability.