title: Nanogold/mesoporous carbon foam-mediated silver enhancement for graphene-enhanced electrochemical immunosensing of carcinoembryonic antigen.
abstract: Nanogold functionalized mesoporous carbon foam (Au/MCF) coupling with a signal amplification by C-Au synergistic silver enhancement was designed for sensitive electrochemical immunosensing of biomarker. The Au/MCF was prepared by in situ growth of nanogold on carboxylated MCF and used as a tracing tag to label signal antibody via the inherent interaction between protein and nanogold. The immunosensor was prepared by covalently immobilizing capture antibody on an electrochemically reduced graphene oxide/chitosan film modified glassy carbon electrode. Through a sandwich-type immunoreaction, Au/MCF tags were captured on the immunoconjugates to induce a silver deposition process. The electrochemical stripping signal of the deposited silver was used to monitor the immunoreaction. The Au/MCF-mediated silver enhancement along with the graphene-promoted electron transfer led to high detection sensitivity of carcinoembryonic antigen. Under optimal conditions, the proposed immunoassay method showed wide linear range from 0.05 pg mL(-1) to 1 ng mL(-1) and a detection limit down to 0.024 pg mL(-1). The newly designed amplification strategy holds great potential for ultrasensitive electrochemical biosensing of other analytes.
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, Department of Chemistry, Nanjing University, Nanjing 210093, PR China.
authors.forename: Dajie
authors.initials: D
authors.lastname: Lin
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.forename: Huangxian
authors.initials: H
authors.lastname: Ju
authors.forename: Feng
authors.initials: F
authors.lastname: Yan
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002244:Carbon / Q000737:chemistry; D002272:Carcinoembryonic Antigen / Q000302:isolation & purification*; D048271:Chitosan / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry; D006801:Humans; D007118:Immunoassay; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry
chemical_list: D002272:Carcinoembryonic Antigen; D012834:Silver; D002244:Carbon; D006046:Gold; D006108:Graphite; D048271:Chitosan
keywords: Electrochemical sensors; Graphene; Immunoassay; Mesoporous carbon foam; Signal amplification; Silver deposition