Interaction of Fructose Dehydrogenase with a Sulfonated Polyaniline: Application for Enhanced Bioelectrocatalysis

We report on efficient bioelectrocatalysis of the redox enzyme fructose dehydrogenase (FDH) upon its interaction with the sulfonated polyaniline PMSA1 (poly(2-methoxyaniline-5-sulfonic acid)-co-aniline). This interaction has been monitored in solution and on the surface of planar and macroporous indium tin oxide (ITO) electrodes by UV-vis and cyclic voltammetric measurements. Moreover, an enhancement of the catalytic activity for fructose conversion induced by a structural change of sulfonated polyaniline PMSA1 caused by the presence of Ca2+ ions is observed. An entrapment of the Ca2+-bound polymer and enzyme inside the pores of macroporous ITO electrodes leads to a significantly increased (similar to 35-fold) bioelectrocatalytic signal in comparison to that of a flat ITO and allows the fabrication of highly efficient electrodes with good stability.