A new method for dispersing palladium microparticles in conducting polymer films and its application to biosensors

Composite films of polypyrrole/sulfated poly(β-hydroxyethers) (PPy/S-PHE) are electrically conducting and mechanically flexible. Palladium particles were dispersed in the films by thermally decomposing bis(dibenzylideneacetone)palladium(0) complex which had been absorbed by the films from a CHCl3 solution. This method for loading metal particles was enabled by the high affinity of the composite films for organic compounds. Transmission electron microscopy (TEM) and energy-dispersive X-ray spectrometry (EDX) analyses revealed that fine palladium particles in the nanometer range are dispersed in the PPy/S-PHE conducting films. A glucose sensor based on the detection of hydrogen peroxide was prepared by immobilizing glucose oxidase (GOD) using glutaraldehyde on a Pd/PPy/S-PHE electrode. This biosensor responded to glucose even at 400 mV versus Ag/AgCl, which is lower than the working potential of conventional glucose sensors prepared on a platinum electrode.