(331c) Fabrication and Characterization of Enzyme Nanoparticles

There has been considerable interest in recent years in synthesizing nanostructured materials because of their unique optical, electronic, chemical, and mechanical properties. Special attention has been given to bioassay applications using such nanomaterials to develop biosensors, biomedical devices, biofuel cells and bioreactors. DNA, antibodies and enzymes have been immobilized to nanostructured materials by covalent binding, adsorption, and entrapment to develop such sensitive bioassay methods. Among these, enzyme nanoparticles show promise in the ability to tailor their properties through immobilization, which provide many advantages such as enhanced stability and easy separation from reaction mixtures. We explored three types of enzyme immobilization: binding to stimuli responsive polymers and cross-linking to a magnetic nanoparticle core, and immobilization of enzyme nanoparticles to electrode surfaces. Cross-linking methods, while reducing the overall enzymatic activity, retained activity for longer periods of time. The recoverable formats also maintained consistent activity through multiple cycles. Size dependence of activity of enzyme per gram of the biocatalyst was also explored.