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

• 来源期刊: 中国科学:化学（英文版）
• 年，卷（期）: 2018,（4）
• 页码范围: 476-482
• 页数: 7页
• 语种: 英文

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 CuSO4-ascorbic acid reduction,because both C-dots and AuNPs could strongly catalyze the CuSO4 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 immunoanalysis,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.