title: Proximity hybridization-regulated electrochemical stripping of silver nanoparticles via nanogold induced deposition for immunoassay.
abstract: A simple and disposable electrochemical immunosensor was developed for sensitive and selective detection of a protein biomarker via target-induced proximity hybridization and electrochemical stripping analysis of silver nanoparticles (AgNPs). The immunosensor was prepared by assembling single-stranded DNA modified gold nanoparticles (ssDNA@AuNPs) on a graphene oxide modified disposable screen-printed carbon electrode (SPCE). In the presence of a target protein and two DNA-labeled antibodies, the proximate complex formed in homogeneous solution could hybridize with the assembled DNA to take away AuNPs, which decreased AuNP-catalyzed deposition of AgNPs on the immunosensor surface, and thus the anodic stripping signal. The proposed method avoided the interference of dissolved oxygen. Using the carcinoembryonic antigen (CEA) as a model analyte, this method showed a linear range of four magnitude orders with a detection limit down to 3.9 pg mL(-1). The electrochemical immunosensor possessed preparation convenience, good stability and high sensitivity, and could be extended to sensitive biosensing of other analytes, showing potential application in point-of-care testing.
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P.R. China. hxju@nju.edu.cn.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.forename: Lin
authors.initials: L
authors.lastname: Cui
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Liu
authors.forename: Feng
authors.initials: F
authors.lastname: Yan
authors.forename: Huangxian
authors.initials: H
authors.lastname: Ju
mesh_terms: D001483:Base Sequence; D015374:Biosensing Techniques / Q000379:methods*; D002272:Carcinoembryonic Antigen / Q000097:blood; D004277:DNA, Single-Stranded / Q000737:chemistry / Q000235:genetics; D004595:Electroplating / Q000379:methods*; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009693:Nucleic Acid Hybridization; D019095:Point-of-Care Systems; D012834:Silver / Q000737:chemistry*
chemical_list: D002272:Carcinoembryonic Antigen; D004277:DNA, Single-Stranded; D012834:Silver; D006046:Gold