IMPROVEMENT OF POLY(AMPHIPHILIC PYRROLE) ENZYME ELECTRODES VIA THE INCORPORATION OF SYNTHETIC LAPONITE-CLAY-NANOPARTICLES

The electropolymerization of an enzyme-amphiphilic pyrrole ammonium-la ponite nanoparticles mixture preadsorbed on the electrode surface prov ides the simultaneous immobilization of the enzyme and the hydrophilic laponite-clay-nanoparticles in a functionalized polypyrrole film. The presence of incorporated laponite particles within the electrogenerat ed polymer induces a strong improvement of the analytical performances (I-max and sensitivity) of amperometric biosensors based on polypheno l oxidase. These beneficial effects have been attributed to a marked e nhancement of the apparent specific activity of the immobilized enzyme (from 0.21 to 0.85% of the specific activity of the free enzyme), the permeability of the host polymer being unchanged. This strategy of bi osensor performance improvement was tested with cholesterol oxidase as an enzyme model. The presence of laponite additive in the poly(amphip hilic pyrrole) host matrix induces a similar enhancement of sensitivit y and I-max for cholesterol biosensing as well as a large improvement of the storage stability of the polypyrrole-cholesterol oxidase electr ode. (C) 1997 Elsevier Science B.V.