Efficiency of a bienzyme sequential reaction system immobilized on polyelectrolyte multilayer-coated colloids.

We assembled multilayer films of glucose oxidase (GOx) and horseradish peroxidase (HRP) coimmobilized together with polyelectrolyte layers on the surface of silica microparticles. The influence of different polyelectrolyte combinations on the immobilization and functionality of the enzymes was examined for several multilayer configurations. Precomplexation of the enzymes with a polyvinylpyridine-based polyamine allowed the stable adsorption of enzyme layers without affecting their catalytic activity. The efficiency of the sequential reaction between GOx and HRP on the surface of the colloids was quantitatively analyzed and rationalized in terms of the kinetic parameters of both enzymes and the reaction-diffusion kinetics of the system. In the optimized configuration, with GOx and HRP coimmobilized in the same layer, the overall rate of hydrogen peroxide conversion was around 2.5 times higher than for GOx and HRP in separate layers or for equivalent amounts of both enzymes free in solution.