Moisture-activated, electrically conducting bioadhesive interfaces for biomedical sensor applications

Abstract

An electrically conducting interface for biomedical sensors, formed by casting and drying a polymer blend containing poly(methyl vinyl ether–maleic anhydride), glycerin as plasticizer, polyvinylpyrrolidone as viscosity builder and sodium chloride as the conducting electrolyte, is described. The resulting flexible bioadhesive film can adhere to a biological substrate under adverse conditions such as high humidity or when the biological substrate is immersed in water or a physiological fluid. The technology allows the design, for example, of an electrode for the monitoring of foetal heart rate and other physiological and analytical sensors. The effect on interface bioadhesion of varying both the composition of the polymer blend and the ambient moisture conditions on storage were investigated in respect of bioadhesion to a model substrate (wet neonate porcine skin) and the mechanical behaviour of the the interface. Optimum bioadhesive performance was obtained from films formulated from blends (pH 5) containing copolymer–plasticizer (2 + 1) and 5% m/m polyvinylpyrrolidone. Moisture conditions on storage had a significant effect on both the subsequent bioadhesive performance and the mechanical properties of the stored films. Formulation and hydration interactions were identified using 2 × 2 factorial design experiments. Data analysis was by a two-way ANOVA with repeated measures.