纳米金信号探针/石墨烯修饰免疫传感器检测微囊藻毒素

摘要

利用石墨烯纳米片层(GS)偶联牛血清白蛋白(BSA)标记的微囊藻毒素(MCLR)(BSA-MCLR)构建了纳米金(AuNPs)为信号探针的电流型免疫传感器.分别用扫描电子显微镜(SEM)、透射电子显微镜(TEM)和紫外-可见吸收光谱对合成纳米材料进行表征;用循环伏安法研究修饰电极表面的电化学特性.通过待测MCLR与固定的BSA-MCLR竞争结合抗体(anti-MCLR),之后恒电位将AuNPs氧化为AuCl4-,再利用差分脉冲伏安法(DPV)进行阴极电位扫描,还原AuCl4为Au,以产生的峰电流值为检测信号,测定MCLR浓度.最佳实验条件下,用免疫传感器测定MCLR的线性范围为0.1～ 50 μg/L,检出限为0.05 μg/L.对传感器的重现性、稳定性和选择性进行了考察.相较于酶标探针,以AuNPs为信号探针标记抗体,可使检测过程更经济便捷,稳定性更强,检测效果良好.%Using graphene sheet(GS) as a matrix connecting bovine serum albumin to label microcystins (MCLR) (BSA-MCLR),an electrochemical immunoseusor was developed for the determination of MCLR with AuNPs as a signal probe.Scanning electron microscopy (SEM),transmission electron microscopy(TEM) and UV-Vis absorption spectroscopy were used to characterize the synthetic nanomaterials.Cyclic voltammetry was used to investigate the electrochemical properties of the modified electrodes.Analyte MCLR was competitively combined with immobilized BSA-MCLR to form anti-MCLR.After the immune reaction,AuNPs were electrochemically oxidized into AuCl4-at a constant potential.Then the AuCl4-ions were reduced into Au with the peak current as the detecting signal via cathodic potential scan of differential pulse voltammetry (DPV).Under the optimal conditions,the linear range was from 0.1 μg/L to 50 μg/L with a detection limit of 0.05 μg/L.The reproducibility,stability and selectivity of the immunosensor were investigated.Compared with the enzyme-labeled probes,the AuNPs labeled probe could have the determined process finished with low cost,high stability and excellent detection result.