A novel electrochemical SPR biosensor

In this paper, we demonstrate for the first time that upon electrochemical oxidation/reduction, the transition in the conductivity of polyaniline (PAn ) film on gold electrode surface leads to a large change of surface plasmon resonance (SPR) response due to a change in the imaginary part of dielectr ic constant of PAn film. Based on the amplifying response of SPR to the red ox transformation of PAn film as a direct result of the enzymatic reaction between horseradish peroxidase (HRP) and PAn in the presence of H2O2, a nov el PAn-mediated HRP sensor has been fabricated. The electrochemical SPR bio sensor, unlike a usual binding assay with SPR, can afford a larger SPR resp onse, and can also be reused by reducing the PAn film electrochemically to its reduced state. This method opens up a new route to the fabrication of S PR biosensor. (C) 2001 Elsevier Science BN. All rights reserved.