A Nanocatalyst-Based Assay for Proteins:  DNA-Free Ultrasensitive Electrochemical Detection Using Catalytic Reduction of <i>p</i>-Nitrophenol by Gold-Nanoparticle Labels

Abstract

This communication reports a nanocatalyst-based electrochemical assay for proteins. Ultrasensitive detection has been achieved by signal amplification combined with noise reduction: the signal is amplified both by the catalytic reduction of p-nitrophenol to p-aminophenol by gold-nanocatalyst labels and by the chemical reduction of p-quinone imine to p-aminophenol by NaBH4; the noise is reduced by employing an indium tin oxide electrode modified with a ferrocenyl-tethered dendrimer and a hydrophilic immunosensing layer.