基于纳米金/多壁碳纳米管-普鲁士蓝-壳聚糖纳米复合物/蛋白A定向固定甲胎蛋白免疫传感器的研究

Direct fixation of alpha-fetoprotein immunosensor based on multi-wall carbon nanotubes-Prussian blue-chitosan nanocomposite and protein A

目的以金纳米粒子修饰的氧化铟锡(ITO)玻璃为基底电极,将多壁碳纳米管-普鲁士蓝-壳聚糖(MWNTs-PB-CHIT)纳米复合物及蛋白A(PA)共修饰于其表面固载抗体制得高灵敏甲胎蛋白(AFP)电流型免疫传感器。方法先在ITO电极表面电沉积一层纳米金,随后将MWNTs-PB-CHIT纳米复合物滴涂于ITO玻璃电极的纳米金膜上,最后利用壳聚糖的吸附性及在酸性(pH=6.5)环境的负电性,静电吸附蛋白A并定向固定甲胎蛋白抗体(anti-AFP),制得电流型免疫传感器。结果在最佳实验条件下,该传感器响应的峰电流值与AFP浓度在1.0～250.0ng/ml的范围内保持良好的线性关系,检测下限为0.5ng/ml,反应达到稳定电流所用时间为6min,并且电流值相对标准差小于3%。结论成功构建一次性使用、价格低廉的新型传感器电极材料。

Objective To construct the highly alpha-fetoprotein （AFP） sensitive immunosensor based on multi-wall carbon nanotubes-prussian blue-chitosan （MWNTs-PB-CHIT） nanocomposite and protein A （PA） using indium tin oxides （ITO） electrode. Methods Nano-Au was electrically deposited on the surface of ITO electrode. MWNTs-PB-CHIT nanocomposite was dropped onto the ITO electrode surface modified by gold nanoparticles. PA on the composite surface was adsorbed through the electrostatic and chitosan force with negative charge for immobilizing AFP antibodies at pH 6.5. Results The peak current value of the immunosensor was linearly related with the AFP at a concentration of 1.0 to 250.0 ng/ml level with a detection limit of 0.5 ng/ml. The response time of stable current was 6 min and the RSD of the current was less than 3%. Conclusion The new immunosensor we constructed is economical and disposable.