Probing of microgel-enzyme films on graphite substrates by means of atomic force microscopy and amperometry

Microgel-enzyme coatings were fabricated onto graphite substrates (highly oriented pyrolytic graphite or graphitebased screen-printed electrodes) via two-stage sequential procedure, which consists in adsorption of a pH- and temperature-sensitive copolymer microgel, followed by electrostatic immobilization of glucose oxidase into the microgel film. The microgel-enzyme coatings were examined by means of atomic force microscopy showing remarkable coverage of graphite surface by the microgels and visualizing the immobilized enzyme. Finally, amperometry was applied to reveal the effect of the polymeric (microgel) matrix on temperature behavior of glucose oxidase in the microgel- enzyme coatings.