C-dots assisted synthesis of gold nanoparticles as labels to catalyze copper deposition for ultrasensitive electrochemical sensing of proteins

作     者：Xiaoli Qin Yifan Dong Minghan Wang Zhiwei Zhu Meixian Li Xiangjian Chen Di Yang Yuanhua Shao 

作者机构：Beijing National Laboratory for Molecular SciencesCollege of Chemistry and Molecular EngineeringPeking University Institute of Cardiovascular DiseaseFirst Affiliated Hospital of Nanjing Medical University 

出 版 物：《Science China Chemistry》 (中国科学（化学英文版）)

年 卷 期：2018年第61卷第4期

页      面：476-482页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070302[理学-分析化学] 0703[理学-化学] 

基　　金：supported by the National Key Research and Development Program of China(2016YFA0201300) the National Natural Science Foundation of China(21335001,21575006) China Postdoctoral Science Foundation(2016M600846) 

主　　题：gold nanoparticles with C-dots as labels copper deposition reaction for signal enhancement human immunoglobulin G human cardiac troponin I 

摘      要：We report an ultrasensitive protocol for electrochemical sensing using the hydroxyl-rich C-dots assisted synthesis of gold nanoparticles(C-dots@AuNP) as labels with copper depositon reaction. The C-dots catalyzing copper deposition reaction was implemented for the first time. We constructed a sandwich-type immunosensor on the chitosan modified glassy carbon electrode(GCE) by glutaraldehyde(GA) crosslinking, with C-dots@AuNP as biolabels. Copper was deposited on the catalytic surfaces of second antibody-conjugated C-dots@AuNP nanoparticles through CuSO_4-ascorbic acid reduction, because both C-dots and AuNPs could strongly catalyze the CuSO_4 and ascorbic acid to form Cu particles, which amplified the detection signal. Then the corresponding antigen was quantified based on simultaneous chemical-dissolution/cathodic-preconcentration of copper for insitu analysis using anodic stripping square wave voltammetry(ASSWV) directly on the modified electrode. Under optimized conditions, these electrodes were employed for sandwich-type immunoanaly sis, pushing the lower limits of detection(LODs)down to the fg mL^(-1) level for human immunoglobulin G(IgG) and cardiac troponin I(cTnI), a cardiac biomarker. These novel sensors have good stability and acceptable accuracy and reproducibility, suggesting potential applications in clinical diagnostics.