基于聚硫堇/亚甲基蓝和纳米金放大的免疫传感器检测贝类毒素大田软海绵酸  

A Label-free Electrochemical Immunosensor for Okadaic Acid Detection Based on Polythionine / Methylene Blue and Gold Nanoparticles

作　　者：郭萌萌[1] 吴海燕[1] 李兆新[1] 薛瑞宇 谭志军[1] 翟毓秀[1] 沈国励[2] 

机构地区：[1]农业部水产品质量安全检测与评价重点实验室中国水产科学研究院黄海水产研究所,山东青岛266071 [2]湖南大学化学生物传感与计量学国家重点实验室,湖南长沙410082

出　　处：《分析测试学报》2014年第2期161-166,共6页Journal of Instrumental Analysis

基　　金：国家自然科学基金资助项目(41106109);农业部948项目(2013-S8);中央级基本科研业务费资助项目(20603022011004,20603022012019)

摘　　要：采用聚硫堇（PTH）修饰电极为传感界面提供一个生物修饰功能基质膜,借助纳米金（GNPs）的导电性、生物相容性与高比表面积特性实现抗体的有效固定,并以亚甲基蓝（MB）为电子媒介加速电极表面电化学反应的电子传递,构建了一种高灵敏的非标记电化学免疫传感器,用于贝类毒素大田软海绵酸（OA）的检测.当分子结构中含有羧基和酚基的OA与其抗体特异性结合后,生成以阴离子形式存在的抗原-抗体复合物,阻碍了传感器表面电子的传递,导致峰电流下降.利用免疫反应前后峰电流的变化,可对OA进行特异性识别和准确定量.在优化实验条件下,OA浓度的对数在0.2～100 μg/L范围内与其峰电流的变化值（△I）呈线性相关,线性方程为△I=1.721 7＋1.083 6lgρ,相关系数为0.992 0,检出限为0.1μg/L.该免疫传感器重现性好、特异性强,用于实际贝类样品的测定,回收率为85.3％～ 112％.A sensitive,label-free electrochemical immunosensor based on the combination of polythionine/methylene blue（PTH/MB） and gold nanoparticles （GNPs） amplification was proposed for the determination of okadaic acid（OA）.A gold electrode was firstly modified with an electropolymerized film of PTH/MB,which not only provided a stable sensing matrix with abundant amino-groups,but also improved the conductivity of the interface.Subsequently,gold nanoparticle monolayer was assembled onto the resulting surface.Making use of the unique properties of GNPs,antibodies can be self-assembled onto the surface-confined GNPs via amine-Au affinity with a high loading amount and reserve high immunological activity.Due to its ionizable carboxylic and phenolic moieties,OA could offer additional negative charge upon binding to anti-OA.After the introduction of OA,the anion forms of antibody-antigen complex formed on the sensing interface can efficiently block the electron transfer between the redox species and the electrode surface,resulting in a decrease of redox peak current.The current reduction is proportional to amount of analyte.The electrochemical characteristics of the immunosensor were studied by cyclic voltammetry（CV）,electrochemical impedance spectroscopy （EIS） and differential pulse voltammetry（DPV）.The factors influencing the performance of the immunosensor were investigated.Under the optimized experimental conditions,the proposed sensing strategy provides a linear dynamic range from 0.2 μg/L to 100 μg/L and the regression equation was AI =1.721 7 ＋ 1.083 6lgρ with a correlation coefficient of 0.992 0.The detection limit was estimated to be 0.1 μg/L.With excellent selectivity and reproducibility,the proposed immunosensor was applied in the determination of OA in real shellfish samples with spiked recoveries of 85.3%-112%.

关 键 词：非标记电化学免疫传感器 大田软海绵酸 硫堇 亚甲基蓝 纳米金 

分 类 号：O657.1[理学—分析化学] S852.44[理学—化学]