title: Nanosilver-doped DNA polyion complex membrane for electrochemical immunoassay of carcinoembryonic antigen using nanogold-labeled secondary antibodies.
abstract: A simple and sensitive electrochemical immunoassay protocol was developed for the detection of carcinoembryonic antigen (CEA) using nanosilver-doped DNA polyion complex membrane (PIC) as sensing interface. To construct such an immunosensor, double-stranded DNA was initially assembled onto the surface of thionine/Nafion-modified screen-printed carbon electrode to adsorb silver ions with positive charges, then silver ions were reduced to nanosilver particles with the aid of NaBH(4), and then anti-CEA antibodies were immobilized on the nanosilver surface. Gold nanoparticles conjugated with horseradish peroxidase-labeled anti-CEA were employed as signal antibodies for the detection of CEA with a sandwich-type assay format. Under optimal conditions, the immunosensor exhibited a dynamic range of 0.03-32 ng mL(-1) with a low detection limit of 10 pg mL(-1) CEA. Intra- and inter-assay imprecision (CVs) were <9.5% and 6.5%, respectively. The response could remain 90.1% of the original current at 30th day. 50 real samples were evaluated using the immunosensor and the enzyme-linked immunosorbent assay, respectively, and received in accordance with those two methods.
authors.affiliation: Department of Cardiothoracic Surgery, Southwest Hospital, Third Military Medical University, Chongqing 400038, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.forename: Ping
authors.initials: P
authors.lastname: Yi
authors.forename: Ping
authors.initials: P
authors.lastname: He
authors.forename: Tao
authors.initials: T
authors.lastname: Jing
authors.forename: Kelong
authors.initials: K
authors.lastname: Liao
authors.forename: Kang
authors.initials: K
authors.lastname: Yang
authors.forename: Haidong
authors.initials: H
authors.lastname: Wang
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology*; D002244:Carbon / Q000737:chemistry; D002272:Carcinoembryonic Antigen / Q000097:blood* / Q000276:immunology; D004247:DNA / Q000737:chemistry*; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D005465:Fluorocarbon Polymers / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010640:Phenothiazines / Q000737:chemistry; D012834:Silver / Q000737:chemistry*
chemical_list: D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen; D005465:Fluorocarbon Polymers; D010640:Phenothiazines; C040402:perfluorosulfonic acid; D012834:Silver; D002244:Carbon; D006046:Gold; D004247:DNA; D006735:Horseradish Peroxidase; C009469:thionine