title: Sensitive Bioanalysis Based on in-Situ Droplet Anodic Stripping Voltammetric Detection of CdS Quantum Dots Label after Enhanced Cathodic Preconcentration.
abstract: We report a protocol of CdS-labeled sandwich-type amperometric bioanalysis with high sensitivity, on the basis of simultaneous chemical-dissolution/cathodic-enrichment of the CdS quantum dot biolabel and anodic stripping voltammetry (ASV) detection of Cd directly on the bioelectrode. We added a microliter droplet of 0.1 M aqueous HNO₃ to dissolve CdS on the bioelectrode and simultaneously achieved the potentiostatic cathodic preconcentration of Cd by starting the potentiostatic operation before HNO₃ addition, which can largely increase the ASV signal. Our protocol was used for immunoanalysis and aptamer-based bioanalysis of several proteins, giving limits of detection of 4.5 fg·mL(-1) for human immunoglobulin G, 3.0 fg·mL(-1) for human carcinoembryonic antigen (CEA), 4.9 fg·mL(-1) for human α-fetoprotein (AFP), and 0.9 fM for thrombin, which are better than many reported results. The simultaneous and sensitive analysis of CEA and AFP at two screen-printed carbon electrodes was also conducted by our protocol.
authors: Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, China. qinxiaoli0413@163.com.
authors: Xiaoli
authors: X
authors: Qin
authors: Liuzhou Traditional Chinese Medicine Hospital, Liuzhou 545001, China. wllk2000@163.com.
authors: Linchun
authors: L
authors: Wang
authors: Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha 410081, China. xieqj@hunnu.edu.cn.
authors: Qingji
authors: Q
authors: Xie
mesh_terms: D052158:Aptamers, Peptide; D001681:Biological Assay / Q000379:methods*; D019187:Cadmium Compounds / Q000737:chemistry*; D002272:Carcinoembryonic Antigen / Q000097:blood; D003198:Computer Simulation; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D006801:Humans; D007118:Immunoassay; D007074:Immunoglobulin G / Q000097:blood; D045663:Quantum Dots / Q000737:chemistry*; D013194:Staining and Labeling; D013440:Sulfides / Q000737:chemistry*; D013917:Thrombin / Q000032:analysis; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D052158:Aptamers, Peptide; D019187:Cadmium Compounds; D002272:Carcinoembryonic Antigen; D007074:Immunoglobulin G; D013440:Sulfides; D000509:alpha-Fetoproteins; C034939:cadmium sulfide; D013917:Thrombin
keywords: CdS quantum dot-labeled amperometric bioanalysis; aptamer-electrode; immunoelectrode; screen-printed carbon electrodes; signal amplification