基于多壁碳纳米管-壳聚糖-硫堇纳米复合物修饰甲胎蛋白免疫传感器的研究

An immunosensor for α-fetoprotein based on multi-wall carbon nanotube-chitosan-Thionine nanocomposite

目的采用多壁碳纳米管-壳聚糖-硫堇(MWCNT-CS-THi)纳米复合物及半胱氨酸盐酸盐共修饰于玻碳电极表面固载抗体制得高灵敏甲胎蛋白免疫传感器。方法先在玻碳电极表面滴涂一层MWCNT-CS-THi纳米复合物,随后利用壳聚糖和硫堇分子中大量的正电荷氨基固定纳米金(GNPs)并吸附半胱氨酸盐酸盐(CH),最后用戊二醛(GA)交联甲胎蛋白特异性抗体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甲胎蛋白抗原(AFP)浓度在0.1～200.0ng/ml的范围内保持良好的线性关系,检测下限为0.07ng/ml。结论成功建立了甲胎蛋白免疫传感器,该方法制备简单,线性范围宽,检测下线低。

Objective To design a new immunosensor for the detection of α-fetoprotein （AFP） antigen based on multi-wall carbon nanotube-chitosan-Thionine （MWCNT-CS-THi） nanocomposite with cysteine hydrochloride （CH） and gold nanoparticles （GNPs） modified glassy carbon electrode （GCE）. Methods Firstly, MWCNT-CS-THi composite was dropped onto the surface of the GCE. Subsequently, GNPs were adsorbed onto the nanocomposites surface through positive charge of thionine and chitosan for immobilizing CH. Finally, glutaraldehyde （GA） cross-linking method was employed to immobilize AFP antibodies on the electrode surface. Thus, the finished immunosensor was constructed. The experimental condition was optimized through changing pH of the system and incubation time. The stability, specificity and repetitiveness of the system were evaluated. Results The optimal pH value was 6.5, and incubation time was 20 min. Under optimal conditions, the proposed immunosensor displayed a broader linear response to AFP, with a working range from 0.1 to 200.0 ng/ml and a detection limit of 0.07 ng/ml. Sound stability, specificity and repetitiveness were obtained in our immunosensor for AFP detection. Conclusion Our self-made immunosensor is easy to produce, and has high sensitivity, wide detection range and low detection limit.