基于纳米金与碳纳米管-纳米铂-壳聚糖纳米复合物固定癌胚抗原免疫传感器的研究

采用纳米金(nano-Au)、多壁碳纳米管-纳米铂-壳聚糖的纳米复合物(MWNT-Pt-CS)及电子媒介体硫堇(Th)固载抗体制得高灵敏癌胚抗原免疫传感器．首先, 于壳聚糖溶液中用NaBH4还原H2PtCl6, 并将多壁碳纳米管分散于其中制得碳纳米管-纳米铂-壳聚糖纳米复合物, 并将其滴涂在玻碳电极上成膜; 然后, 吸附电子媒介体硫堇制得硫堇/碳纳米管-纳米铂-壳聚糖(Th/MWNT-Pt-CS)修饰电极．利用壳聚糖和硫堇分子中大量的氨基固定纳米金并吸附癌胚抗体(anti-CEA); 最后, 用辣根过氧化物酶(HRP)封闭活性位点从而制得高灵敏电流型免疫传感器．在优化的实验条件下, 该传感器响应的峰电流值与癌胚抗原(carcinoembryonic antigen)浓度在0.5～10和10～120 ng/mL的范围内保持良好的线性关系, 检测限为0.2 ng/mL．

An Immunosensor for Carcinoembryonic Antigen Based on Gold Nanoparticles and Multi-wall Carbon Nanotube-Pt-chitosan Composite

A highly sensitive amperometric immunosensor for the determination of carcinoembryonic antigen (CEA) was developed. In the solution of nano-Pt doped (Pt-CS), multi-wall carbon nanotubes (MWNT) were ultrasonically dispersed to give a multi-wall carbon nanotube-Pt-chitosan composite (MWNT-Pt-CS). Firstly, this composite was modified on a glassy carbon electrode surface, and then thionine was coated onto it. Subsequently, gold nanoparticles (nano-Au) were adsorbed onto the composite surface through the amino groups of thionine and chitosan for immobilizing CEA antibodies. Finally, horseradish peroxidase (HRP) was employed to block the possible remaining active sites of nano-Au layer to avoid the non-specific adsorption. Under the optimized conditions, the response current of the proposed immunosensor decreased linearly in two concentration ranges of CEA from 0.5 to 10 ng/mL and from 10 to 120 ng/mL with a detection limit of 0.2 ng/mL.