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 

机构地区：[1]Beijing National Laboratory for Molecular Sciences,College of Chemistry and Molecular Engineering,Peking University [2]Institute of Cardiovascular Disease,First Affiliated Hospital of Nanjing Medical University

出　　处：《Science China Chemistry》2018年第4期476-482,共7页中国科学（化学英文版）

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)

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.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.

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

分 类 号：O657.1[理学—分析化学]