(582i) Polymer-Conjugated Enzyme Biohybrid Carriers for Detoxification Processes-Internal Diffusion and Kinetics

Polymer-Conjugated Enzyme Biohybrid Carriers for Detoxification Processes-Internal Diffusion and Kinetics

Robert J. Compton(1), Matthew W. Eggert(1,2), Mark E. Byrne(1,2), Robert P. Chambers(1)

1. Department of Chemical Engineering, Auburn University

2.Biomimetic & Biohybrid Materials, Biomedical Devices, and Drug Delivery Laboratories, Department of Chemical Engineering, Auburn University

Biohybrid materials, or materials utilizing biological materials in their rational design, are prime candidates to act as therapeutic carriers for detoxification processes. Our group has previously introduced a biomimetic hybrid structure capable of effective ethanol reaction catalyzed by alcohol dehydrogenase covalently bound to a suitable hydrogel through multipoint attachment. This biohybid material is yeast alcohol dehydrogenase covalently attached to a poly(MAA-coPEG200MA-coPEG200DMA) pH sensitive hydrogel network via UV free-radical polymerization following functionalization of the enzyme amino groups with acryloyl chloride. The acryloyl chloride enables multipoint attachment of the polymer to the enzyme by acylating the enzyme at multiple amino groups.

The biohybrid material, alcohol dehydrogenase covalently attached to the hydrogel polymer through multipoint attachment, was studied extensively to determine its intrinsic rate expression and kinetic parameters, including enzyme activity, ethanol, acetaldehyde, [NAD⁺] and NADH kinetic constants, for comparison to those for the free enzyme. The effect of internal diffusion on the performance of this biohybrid material was investigated experimentally by using hydrogels of varying characteristic lengths and varying enzyme loading. Internal diffusion effects were also studied through computer simulations using the intrinsic rate expression together with literature diffusivities of ethanol, acetaldehyde, [NAD⁺] and NADH to develop appropriate Thiele moduli to properly interpret the above internal diffusion experimental effectiveness factor kinetic data.

Biohybrid materials, although quite complex, show tremendous potential as multi-enzyme therapeutic carriers for detoxification processes.