Moisture-activated, electrically conducting bioadhesive hydrogels as interfaces for bioelectrodes: Effect of formulation factors on cutaneous adherence in wet environments

The effect of varying the composition of a polymer blend containing poly(methylvinyl ether‐maleic anhydride) copolymer on the Brookfield viscosity of the blend and on the in vitro bioadhesive forces of resultant cast films was assessed. An increase in copolymer concentration increased both blend viscosity and film bioadhesion. Increasing the plasticizer concentration did not significantly alter bioadhesion but did influence film flexibility. Blend pH affected both viscosity and bioadhesion. However, for films to be biocompatible, formulation within the skin pH range was desirable. Films exhibited the ability to ‘restick’ after initial adherence, allowing repositioning of the adhered film in vivo. Factorial design experiments (22) showed that an additive bioadhesive effect occurred when copolymer and PVP concentrations were increased in the polymer blend. However, no interaction between copolymer and plasticizer was observed. Addition of sodium chloride to the polymer blend, necessary to render films electrically conducting for use as bioelectrode interfaces, decreased blend viscosity but did not exert a significant effect on film bioadhesion. © 1995 John Wiley & Sons, Inc.