In this work, the luminophor tris (4,4'-dicarboxylicacid-2,2'-bipyridyl) ruthenium (II) dichloride (Ru(dcbpy)32+) was linked to coreactant polyethylenimine (PEI) with effectively shorted distance, forming a novel self-enhanced PEI-Ru(II) complex to fabricate ultrasensitive electrochemiluminescence immunosensor for carcinoembryonic antigen (CEA) detection by using polyamino acid l-cysteine (pL-Cys) as booster for further signal amplification. The light-emitting species (PEI-Ru(II)*) based on intramolecular electron transfer between PEI• and Ru(III) could efficiently amplify the ECL signal of Ru(dcbpy)32+ owing to its benefit for electron transmission. Secondly, the pL-Cys film was fabricated on the glassy carbon electrode by cyclic voltammogram. After that, the pL-Cys acted as a strongly reducing radical could react with PEI-Ru(III) to generate the excited state PEI-Ru(II)*, which further amplify the ECL signal. With the signal amplification factors, the prepared ECL immunosensor exhibited great advantages in simplification, rapidity, stability and selectivity. Furthermore, the linear range for the determination of CEA was from 0.10 pg/mL to 80 ng/mL with a correlation coefficient of 0.9942 and a detection limit of 0.045 pg/mL (S/N = 3).

中文翻译：

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自增强PEI-Ru(II)复合物以聚氨基酸为助推器构建超灵敏电化学发光免疫传感器用于癌胚抗原检测

在这项工作中，发光体三 (4,4'-二羧酸-2,2'-联吡啶) 二氯化钌 (II) (Ru(dcbpy)32+) 与共反应物聚乙烯亚胺 (PEI) 以有效短距离连接，形成新型自增强 PEI-Ru(II) 复合物制造用于癌胚抗原 (CEA) 检测的超灵敏电化学发光免疫传感器，使用聚氨基酸 l-半胱氨酸 (pL-Cys) 作为进一步信号放大的助推器。基于 PEI• 和 Ru(III) 之间分子内电子转移的发光物质 (PEI-Ru(II)*) 可以有效地放大 Ru(dcbpy)32+ 的 ECL 信号，因为它有利于电子传输。其次，通过循环伏安图在玻碳电极上制备了 pL-Cys 薄膜。之后，pL-Cys 作为强还原自由基可以与 PEI-Ru(III) 反应生成激发态 PEI-Ru(II)*，进一步放大 ECL 信号。由于信号放大因素的影响，所制备的ECL免疫传感器在简单性、快速性、稳定性和选择性方面表现出很大的优势。此外，CEA 测定的线性范围为 0.10 pg/mL 至 80 ng/mL，相关系数为 0.9942，检测限为 0.045 pg/mL (S/N = 3)。