title: Study on the immobilization of anti-IgG on Au-colloid modified gold electrode via potentiometric immunosensor, cyclic voltammetry, and electrochemical impedance techniques.
abstract: The immobilization of anti-IgG on Au-colloid modified gold electrodes has been investigated. A cleaned gold electrode was first immersed in a mercaptoethylamine (AET) solution, and then gold nanoparticles were chemisorbed onto the thiol groups of the mercaptoethylamine. Finally, anti-IgG was adsorbed onto the surface of the gold nanoparticles. Potentiometric immunosensor, cyclic voltammetry, and electrochemical impedance techniques were used to investigate the immobilization of anti-IgG on Au colloids. In the impedance spectroscopic study, an obvious difference of the electron transfer resistance between the Au-colloid modified electrode and the bare gold electrode was observed. The cyclic voltammogram tends to be more irreversible with increased anti-IgG concentration. Using the potentiometric immunosensor, the proposed technique is based on that the specific agglutination of antibody-coated gold nanoparticles, averaging 16 nm in diameter, in the presence of the corresponding antigen causes a potential change that is monitored by a potentiometry. It is found that the developed immunoagglutination assay system is sensitive to the concentration of IgG antigen as low as 12 ng mL(-1). Experimental results showed that the developed technique is in satisfactory agreement with the ELISA method, and that gold nanoparticles can be used as a biocompatible matrix for antibody or antigen immobilization.
authors.affiliation: Chong Qing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest China Normal University, Chongqing 400715, PR China.
authors.forename: Yingzi
authors.initials: Y
authors.lastname: Fu
authors.forename: Ruo
authors.initials: R
authors.lastname: Yuan
authors.forename: Dianping
authors.initials: D
authors.lastname: Tang
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Chai
authors.forename: Lan
authors.initials: L
authors.lastname: Xu
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D017097:Electric Impedance; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D004583:Electrons; D004797:Enzyme-Linked Immunosorbent Assay; D006046:Gold; D017979:Gold Colloid / Q000737:chemistry*; D007118:Immunoassay; D007074:Immunoglobulin G / Q000737:chemistry*; D049329:Nanostructures; D036103:Nanotechnology; D011199:Potentiometry
chemical_list: D001672:Biocompatible Materials; D017979:Gold Colloid; D007074:Immunoglobulin G; D006046:Gold