Block copolymer microdomains: a novel medium for enzymatic reactions.

Block copolymers exhibit the phenomenon of microdomain formation in pure states as well as in solutions. The microdomains vest the block copolymer assemblies with the intriguing characteristics of microheterogeneous media. We demonstrate that this microheterogeneity in hydrophobic-hydrophilic block copolymer systems can be exploited for immobilizing enzymes and to carry out enzymatic reactions. Examples involving cholesterol oxidase and horseradish peroxidase are provided here. The observed changes in the enzymatic activity in block copolymer microdomains from that in the aqueous media are interpreted in terms of the hydrophobicity of the reaction microenvironment. The block copolymer microdomains are simple to generate, well defined, and easily reproducible. Therefore, they hold significant potential as media for enzymatic biosynthetic reactions when the substrates or the reaction products are water insoluble.