An electrochemical biosensor for α-fetoprotein based on carbon paste electrode constructed of room temperature ionic liquid and gold nanoparticles

A novel and effective electrochemical immunosensor for the rapid determination of alpha-fetoprotein (AFP) based on carbon paste electrode (CPE) consisting of room temperature ionic liquid (RTIL) N-butylpyridinium hexafluorophosphate (BPPF6) and graphite. The Surface of the CPE was modified with gold nanoparticles for the immobilization of the alpha-fetoptotein antibody (anti-AFP). By sandwiching the antigen between anti-AFP on the CPE modified with gold nanoparticles and the secondary antibody, polyclonal anti-human-AFP labeled with horseradish peroxidase (HRP-labeled anti-AFP), the immunoassay was established. The concentration of AFP was determined based on differential pulse voltammetry (DPV) signal, which was generated in the reaction between O-aminophenol (OAP) and H2O2 catalyzed by HRP labeled oil the sandwich immunosensor AFP concentration Could be measured in a linear range of 0.50-80.00 ng mL(-1) with a detection limit of 0.25 ng mL(-1). The immunosensor exhibited high sensitivity and good stability. and would be valuable for clinical assay of AFP. (c) 2009 Elsevier B.V. All rights reserved.