Ultrathin Porous Carbon Films as Amperometric Transducers for Biocatalytic Sensors

Novel ultrathin (0.4 [mu]m) porous carbon films are employed as transducers for amperometric biosensors. Such foamlike nanoscopic films couple the advantages of high enzyme loadings (within the micropore hosts) and large microscopic area with a small geometric area. Both electropolymerization and metalization are used to entrap the enzyme within the micropores. Scanning electron microscopy sheds useful insights into the unique morphology of the growing enzyme layer. The greatly enhanced sensitivity is coupled with a fast and stable response. Factors influencing the performance of porous-film-based biosensors are examined and discussed. The improved performance is illustrated in connection with glucose and phenol sensors. The latter offers a remarkably low detection limit of 2.5 x 10[sup [minus]8] M. The new nanoscopic foams should prove useful for many other electroanalytical applications. 11 refs., 7 figs.