Characterization of Enzyme-Redox Hydrogel Thin-Film Electrodes for Improved Utilization

Abstract

Homogeneous, sub-micron thick bioactive films containing redox hydrogels and the enzyme laccase were prepared on gold-coated glass slides via convective self-assembly. Sub-micron film thickness (∼10–50 nm) allowed higher mediator and enzyme utilization by lowering transport limitations. This study demonstrates control of redox hydrogel film morphology by manipulating hydrophilicity, spreading and wetting properties of the hydrogel/electrode interface. Use of a non-ionic surfactant (Triton X-100) enabled spreading of enzyme containing precursor solutions with no negative impact on enzyme activity. Ellipsometry was used to measure film-swelling properties of these systems, square wave voltammetry was employed to estimate the amount of electroactive redox polymer, and cyclic voltammetry enabled estimation of apparent electron diffusivity. This study impacts the design of thin, catalytic films for bioelectronic applications.