He Ying, Chai Yaqin, Yuan Ruo, Wang Haijun, Bai Lijuan, Liao Ni
Education Ministry Key Laboratory on Luminescence and Real-Time Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, People's Republic of China.
Analyst. 2014 Oct 21;139(20):5209-14. doi: 10.1039/c4an01002g.
An electrochemiluminescence (ECL) immunoassay protocol was developed based on mimic-intramolecular interaction for sensitive detection of prostate specific antigen (PSA). It was constructed by integrating the ECL luminophore (tris(4,4'-dicarboxylicacid-2,2'-bipyridyl)-ruthenium(ii)dichloride (Ru(dcbpy)3(2+))) and coreactant (histidine) into the supersandwich DNA structure. This strategy was more effective in amplifying the ECL signal by shortening the electronic transmission distance, improving the ECL luminous stability and enhancing the ECL luminous efficiency. The ECL matrices denoted as MWCNTs@PDA-AuNPs were fabricated through spontaneous oxidative polymerization of dopamine (DA) on multiwalled carbon nanotubes (MWCNTs) and reducing HAuCl4 to produce gold nanoparticles (AuNPs) by DA simultaneously. Then, the prepared matrices were applied to bind capture antibodies. Moreover, supersandwich Ab2 bioconjugate was designed using a PAMAM dendrimer to immobilize the detection antibody and supersandwich DNA structure. The PAMAM dendrimer, with a plurality of secondary and tertiary amine groups, not only facilitated high-density immobilization of the detection antibody and supersandwich DNA structure, but also greatly amplified the ECL signal of Ru(dcbpy)3(2+). The supersandwich DNA structure contained multiple Ru(dcbpy)3(2+) and histidine, further amplifying the ECL signal. The proposed supersandwich immunosensor showed high sensitivity with a detection limit of 4.2 fg mL(-1) and a wide linear range of 0.01 pg mL(-1)-40.00 ng mL(-1). With the excellent stability, satisfying precision and reproducibility, the proposed immunosensor indicates promising practicability for clinical diagnosis.
基于模拟分子内相互作用开发了一种用于灵敏检测前列腺特异性抗原（PSA）的电化学发光（ECL）免疫分析方法。通过将ECL发光体（二氯三（4,4'-二羧酸-2,2'-联吡啶）钌（II）（Ru(dcbpy)3(2+)））和共反应剂（组氨酸）整合到超三明治DNA结构中构建而成。该策略通过缩短电子传输距离、提高ECL发光稳定性和增强ECL发光效率，在放大ECL信号方面更有效。通过多巴胺（DA）在多壁碳纳米管（MWCNTs）上自发氧化聚合，同时用DA还原氯金酸（HAuCl4）以制备金纳米颗粒（AuNPs），从而制备了标记为MWCNTs@PDA-AuNPs的ECL基质。然后，将制备的基质用于结合捕获抗体。此外，使用聚酰胺-胺（PAMAM）树枝状大分子设计超三明治Ab2生物共轭物，以固定检测抗体和超三明治DNA结构。具有多个仲胺和叔胺基团的PAMAM树枝状大分子不仅有助于检测抗体和超三明治DNA结构的高密度固定，而且极大地放大了Ru(dcbpy)3(2+)的ECL信号。超三明治DNA结构包含多个Ru(dcbpy)（2+）和组氨酸，进一步放大了ECL信号。所提出的超三明治免疫传感器具有高灵敏度，检测限为4.2 fg mL(-1)，线性范围宽，为0.01 pg mL(-1)-40.00 ng mL(-1)。该免疫传感器具有出色的稳定性、令人满意的精密度和重现性，在临床诊断中显示出良好的实用性。
