Liu Fujing, Chen Huinan, Deng Dongmei, Fan Xinxia, Li Yuanyuan, Madrakian Tayyebeh, Luo Liqiang
School of Medicine, Shanghai University, Shanghai 200444, PR China.
College of Sciences, Shanghai University, Shanghai 200444, PR China.
Bioelectrochemistry. 2022 Oct;147:108200. doi: 10.1016/j.bioelechem.2022.108200. Epub 2022 Jun 30.
In this work, an ultrasensitive immunosensor for amperometric determination of alpha-fetoprotein (AFP) was developed utilizing Ag and Cu nanoparticles on polydopamine (PDA) functionalized cellulose nanofibrils (CNFs) composite (CNFs/PDA/Cu-Ag) as signal amplifier. PDA was first prepared by self-polymerizing of dopamine, and then was adsorbed on CNFs. The obtained CNFs/PDA was applied as substrate to electrolessly deposit Cu-Ag nanoparticles, using NaBH as reducing agent. The structure and morphology of the synthesized CNFs/PDA/Cu-Ag nanocomposite were analyzed through Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction, scanning electron microscopy, particle size analyzer and transmission electron microscopy. The CNFs/PDA/Cu-Ag modified glassy carbon electrode can fix AFP antibody (Ab), and further capture AFP specifically. Electrochemical impedance spectroscopy and cyclic voltammetry were used to characterize the assembly process of immunosensor. The immunoreaction was amplified by electrocatalytical reduction of HO on Cu-Ag nanoparticles, through which AFP was quantitatively detected. The developed sensor exhibits wide linear range of 0.01-100 ng mL (R = 0.9963) with low detection limit of 4.27 pg mL (S/N = 3). In addition, it has been used for the detection of AFP in human serum, manifesting its preeminent application prospect in early liver cancer diagnosis.
在本工作中，开发了一种用于安培法测定甲胎蛋白（AFP）的超灵敏免疫传感器，该传感器利用聚多巴胺（PDA）功能化纤维素纳米纤维（CNFs）复合材料（CNFs/PDA/Cu-Ag）上的银和铜纳米颗粒作为信号放大器。首先通过多巴胺的自聚合制备PDA，然后将其吸附在CNFs上。以所得的CNFs/PDA为基底，使用硼氢化钠作为还原剂，通过化学镀沉积铜-银纳米颗粒。通过傅里叶变换红外光谱、X射线光电子能谱、X射线粉末衍射、扫描电子显微镜、粒度分析仪和透射电子显微镜对合成的CNFs/PDA/Cu-Ag纳米复合材料的结构和形貌进行了分析。CNFs/PDA/Cu-Ag修饰的玻碳电极可以固定AFP抗体（Ab），并进一步特异性捕获AFP。采用电化学阻抗谱和循环伏安法对免疫传感器的组装过程进行了表征。通过铜-银纳米颗粒上过氧化氢的电催化还原放大免疫反应，据此对AFP进行定量检测。所开发的传感器具有0.01-100 ng mL的宽线性范围（R = 0.9963），检测限低至4.27 pg mL（S/N = 3）。此外，该传感器已用于检测人血清中的AFP，在早期肝癌诊断中显示出卓越的应用前景。
