title: Characterization of the gold-catalyzed deposition of silver on graphite screen-printed electrodes and their application to the development of impedimetric immunosensors.
abstract: This paper describes the characterization of the gold-catalyzed deposition of silver on graphite screen-printed electrodes (SPEs) using electrochemical impedance spectroscopy (EIS) and the application of this approach to the development of impedimetric immunosensors. After applying -0.1 V for 45 s, the amount of electrodeposited silver quantitatively changes the magnitude of two elements of the electrical equivalent circuit: the interface capacitance, Ci, and the charge-transfer resistance, R(CT). Better correlations have been found when considering the R(CT) since this parameter is almost exclusively dependent on the amount of deposited silver under these experimental conditions. This approach has been successfully applied to the development of an impedimetric immunosensor for aflatoxin M(1). The R(CT) magnitude shows good correlation with the amount of gold immobilized on the electrode surface after a competitive assay and thus, with the toxin concentration. This approach has been found sensitive in a wide range of concentrations, from 15 to 1000 free-AFM(1) ppt with a limit of detection of 12 ppt.
authors.affiliation: Department of Biochemistry, College of Károly Eszterházy, Eger, Hungary.
authors.forename: Attila
authors.initials: A
authors.lastname: Vig
authors.forename: Xavier
authors.initials: X
authors.lastname: Muñoz-Berbel
authors.forename: Antonio
authors.initials: A
authors.lastname: Radoi
authors.forename: Montserrat
authors.initials: M
authors.lastname: Cortina-Puig
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Marty
mesh_terms: D000327:Adsorption / Q000276:immunology; D016607:Aflatoxin M1 / Q000032:analysis / Q000737:chemistry; D000906:Antibodies / Q000737:chemistry / Q000276:immunology; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002384:Catalysis; D017097:Electric Impedance; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D006046:Gold / Q000737:chemistry* / Q000276:immunology; D017979:Gold Colloid / Q000276:immunology; D006108:Graphite / Q000737:chemistry*; D015203:Reproducibility of Results; D012834:Silver / Q000737:chemistry*
chemical_list: D000906:Antibodies; D017979:Gold Colloid; D012834:Silver; D016607:Aflatoxin M1; D006046:Gold; D006108:Graphite