Sensitivity enhancement and proteins adsorption are the common challenges faced in protein immunoassays. In this work, an ultrasensitive and protein-resistant label-free amperometric immunosening platform for carcinoma antigen-125 (CA125) based on redox polyaniline-polythionine hydrogel (PANI-PThi gel) was developed. The as-prepared hydrogel, which was facilely synthesized by electropolymerization, exhibited good conductivity and strong hydrophilicity while the sensitivity and specificity of the immunosensor can be enhanced. Furthermore, the as-prepared AuNPs functionalized PANI-PThi gel exhibited strong current signal and H2O2 electrocatalytic ability, which guaranteed a large current variable range. Based on these, the prepared immunosensor revealed a wide linear range from 0.0001 U mL-1 to 1 kU mL-1, a limit of detection of 0.00125 U mL-1 and its sensitivity was at least three-fold higher than previous works. More importantly, the prepared immunosensor exhibited excellent specificity, making it capable of assaying CA125 in human serum.

中文翻译：

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聚苯胺-聚硫氨酸氧化还原水凝胶的简便合成：导电、防污和酶联材料，用于针对癌抗原 125 的超灵敏无标记电流免疫传感器

灵敏度增强和蛋白质吸附是蛋白质免疫测定中面临的常见挑战。在这项工作中，开发了一种基于氧化还原聚苯胺-聚硫氨酸水凝胶（PANI-PThi 凝胶）的超灵敏和蛋白质抗性无标记安培免疫检测平台，用于癌抗原-125（CA125）。所制备的水凝胶通过电聚合方法合成，具有良好的导电性和强亲水性，同时可以提高免疫传感器的灵敏度和特异性。此外，所制备的 AuNPs 功能化 PANI-PThi 凝胶表现出强电流信号和 H2O2 电催化能力，保证了较大的电流可变范围。基于这些，制备的免疫传感器显示出从 0.0001 U mL-1 到 1 kU mL-1 的宽线性范围，检测限为 0。00125 U mL-1，其灵敏度至少比以前的作品高出三倍。更重要的是，所制备的免疫传感器表现出优异的特异性，使其能够检测人血清中的 CA125。