Water-proof anti-drying enzymatic O2 cathode for bioelectric skin patch

Abstract

A water-proof anti-drying enzymatic O2 cathode for a deformable bioelectric skin patch was developed by laminating a thin membrane (50 μm thick) of polydimethylsiloxane (PDMS) to a bilirubin oxidase (BOD)-modified carbon fabric (CF) electrode. The PDMS membrane and the CF electrode were adhered so that a microspace serving as the oxygen reservoir was formed at their interface, enabling the operation of the patch even in a soaked condition for more than a few minutes. Even if the oxygen in the reservoir was depleted by soaking for too long, the patch performance could be recovered within a few tens of seconds by taking it out of the water, owing to the excellent oxygen-permeability of the thin PDMS membrane. The anti-drying effect of PDMS prolonged the lifetime of the bioelectric patch wrapped around a finger for more than 3 h while maintaining transdermal current of ∼20 μA cm−2.