Electrochemically and catalytically active layer-by-layer films of myoglobin with zirconia formed by vapor-surface sol–gel deposition

Abstract

Abstract A myoglobin (Mb) film was successfully assembled layer-by-layer with zirconia formed by vapor-surface sol–gel deposition on solid surfaces. The method involved vaporization of zirconium butoxide (Zr(OBu) 4 ) into thin layers of water, forming ZrO 2 sol–gel layers after hydrolysis of Zr(OBu) 4 . Mb was assembled by adsorption alternated with the ZrO 2 layers. The {ZrO 2 /Mb} n layer-by-layer films at pyrolytic graphite electrodes demonstrated a pair of well-defined and nearly reversible CV peaks at about −0.34 V vs SCE, characteristic of Mb Fe(III)/Fe(II) redox couple, and used to catalyze reduction of oxygen and hydrogen peroxide. FTIR spectroscopy and comparison studies with {ZrO 2 /catalase} n films suggest that Mb in the zirconia sol–gel films essentially retains its native structure. Compared with Mb layer-by-layer films assembled with ZrO 2 nanoparticles, {ZrO 2 /Mb} n films showed larger numbers of electroactive bilayers and higher maximum surface concentration of electroactive Mb, which may be related to the unique structure of ZrO 2 sol–gel with higher porosity.