Design and characterization of a galactose biosensor using a novel polypyrrole-hydrogel composite membrane

A rapid, two-step method for constructing galactose biosensors by entrapment of galactose oxidase within a polymeric composite has been developed. The composite material is formed as an interpenetrating network of polypyrrole grown within a UV cross-linked poly(2-hydroxyethyl methacrylate) [p(HEMA)] hydrogel. The optimized galactose biosensor exhibited a linear response range from 5.0 x 10(-5) to 1.0 x 10(-2) M and detection limit of 25 muM toward galactose. The response time of the biosensor was 70 s. The analytical recovery of galactose in serum samples ranged from 97 to 105% with mean coefficients of variation of 3.8% (within-day analyses) and 4.4% (day-to-day analyses). The biosensor was effective in screening up to twice the physiological levels of ascorbate, urate and acetaminophen interferents and retained 70% of initial enzyme activity after 9 months when stored desiccated in the absence of buffer at 4degreesC.