基于Fe_3O_4@Au复合纳米粒子标记抗体的电化学免疫方法用于水体中大肠杆菌的检测

Fe_3O_4@Au Nanoparticles as Labels for Electrochemical Immunodetection of E.coli in Water

合成了Fe3O4@Au复合纳米粒子作为辣根过氧化酶标记抗体的载体,并将该复合纳米粒子标记物应用于电化学放大免疫分析.将电子媒介体硫堇聚合在玻碳电极表面,以纳米金作为固定大肠杆菌抗体的基底,通过辣根过氧化酶催化溶液中H2O2产生的电流信号来测定大肠杆菌.实验结果表明,该方法对水体中大肠杆菌检测的线性范围为50～1×105cfu/mL,检出限为20 cfu/mL.对过富集后的实际水样进行测定,该法结果表明,对水体中大肠杆菌的检测灵敏度达到2 cfu/mL.

Fe3O4@Au nanoparticles were synthesized in this paper.The surface of nanoparticles was modified with horseradish peroxidase（HRP）-anti-E.coli antibody for amplified electrochemical immunoassay of E.coli.Poly-thionine（PTH） film was electro-polymerized on the GCE as an electron-transfer mediator.Gold nanoparticles（GNPs） on the PTH film constructed an effective antibody immobilization matrix.Using the typical sandwich type immmunoassay,E.coli could be detected according to the H2O2 reduction currents catalyzed by HRP labeled on anti-E.coli antibody.The method allowed quantitative determination of E.coli concentration from 50 to 1×105 cfu/mL,with a detection limit of 20 cfu/mL.By introducing pre-enrichment steps,a concentration of 2 cfu/mL E.coli was detected with this method.