Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University , Chongqing 400715, People's Republic of China.
Faculty of Engineering, Department of Materials, Imperial College London , London, United Kingdom.
Anal Chem. 2017 Oct 17;89(20):11076-11082. doi: 10.1021/acs.analchem.7b03125. Epub 2017 Oct 5.
Here, a novel Ru(II)-organic complex (Ru-PEI-ABEI) with high electrochemiluminescence (ECL) efficiency was proposed to construct a sensitive quenching-typed ECL biosensor for C-peptide (C-P) measurement based on the double quenching effect of dopamine (DA). The high ECL efficiency of Ru-PEI-ABEI was originated from the dual intramolecular self-catalysis including intramolecular coreaction between polyethylenimine (PEI) and Ru(bpy)(mcbpy), and intramolecular ECL resonance energy transfer (ECL-RET) from N-(aminobutyl)-N-(ethylisoluminol) (ABEI) to Ru(bpy)(mcbpy), which would generate a strong initial ECL signal. Through sandwiched immunoreaction and 3D DNA walking machine, a certain amount of target C-P was converted to a large amount of intermediate DNA that could further trigger hybridization chain reaction (HCR) to introduce into massive DA which not only could quench the ECL of Ru(bpy)(mcbpy), but also quench the ECL of ABEI. Thus, the double quenching effect of DA would effectively quench the ECL of Ru-PEI-ABEI, leading to an obviously decreased final ECL signal. Thus, a sensitive quenching-typed ECL biosensor was constructed for C-P detection with a linear range from 50 fg mL to 16 ng mL and an estimated detection limit of 16.7 fg mL. The dual intramolecular self-catalyzed strategy and the double quenching strategy based on one quencher to the same luminous reagent proposed in this work would provide new thought in both ECL signal enhancement and quenching efficiency improvement.
这里，提出了一种新型的 Ru(II)-有机配合物（Ru-PEI-ABEI），具有高电化学发光（ECL）效率，可基于多巴胺（DA）的双重猝灭效应构建用于 C 肽（C-P）测量的灵敏猝灭型 ECL 生物传感器。Ru-PEI-ABEI 的高 ECL 效率源于包括聚乙二胺（PEI）和 Ru（bpy）（mcbpy）之间的分子内核心反应以及 N-（氨基丁基）-N-（乙基异鲁米诺）（ABEI）到 Ru（bpy）（mcbpy）的分子内 ECL 共振能量转移（ECL-RET）的双重分子内自催化，这会产生强的初始 ECL 信号。通过夹心免疫反应和 3D DNA 行走机器，将一定量的靶标 C-P 转化为大量的中间 DNA，这些中间 DNA 可以进一步引发杂交链反应（HCR），从而引入大量的 DA，不仅可以猝灭 Ru（bpy）（mcbpy）的 ECL，还可以猝灭 ABEI 的 ECL。因此，DA 的双重猝灭效应会有效地猝灭 Ru-PEI-ABEI 的 ECL，导致最终 ECL 信号明显降低。因此，构建了用于 C-P 检测的灵敏猝灭型 ECL 生物传感器，线性范围为 50 fg mL 至 16 ng mL，估计检测限为 16.7 fg mL。本工作中提出的基于一种猝灭剂对同一发光试剂的双重分子内自催化策略和双重猝灭策略，为 ECL 信号增强和猝灭效率提高提供了新的思路。
