Control of catalytic activity of glucose oxidase in layer-by-layer films of chitosan and glucose oxidase

The suitability of the layer-by-layer (LbL) technique, based on the alternate adsorption of oppositely charged materials, for immobilization of biomolecules has been well established. Achieving optimized results depends on the experimental conditions for film fabrication, and in most cases on the film architecture. In this paper we exploit the high catalytic activity of glucose oxidase (GOD) immobilized in LbL films with chitosan in oxidation reactions of glucose to gluconic acid. In addition to confirming previous works that these LbL films can be used in biosensors, we used the films in the reduction of a gold salt to yield metallic gold nanoparticles. The reaction kinetics was monitored by measuring the plasmon resonance band of gold nanoparticles, where the enzyme catalytic activity was found to be 92% of the activity in a homogeneous environment. This high degree of activity preservation for immobilized GOD is promising for various systems involving catalysis by GOD.