A label-free electrochemical immunoassay for IgG detection based on the electron transfer

In this study a highly selective label-free electrochemical immunoassay strategy based on the charge transport through the multilayer films associated with the electrocatalytic reduction of [Fe(CN)(6)](3-) is proposed using human immunoglobulin G (human IgG) as the model analyte The antibody-antigen complex formed on the sensing interface can efficiently induce change of the surface charge characteristics the conductivity of multilayer film and/or electron transfer distance resulting in an immunoreaction signal The current reduction is proportional to the amount of analyte Under the optimized experimental conditions the proposed sensing strategy provides a linear dynamic range from 10 to 10(4) ng mL(-1) and a detection limit of 3 ng mL(-1) indicating an improved analytical performance This possibly makes it a potential alternative in bioanalysis of proteins and other molecules (C) 2010 Elsevier B V All rights reserved