Synthesis of polymeric microcapsule arrays and their use for enzyme immobilization

Abstract

CURRENT methods for immobilizing enzymes for use in bioreactors and biosensors^1–20 include adsorption on or covalent attachment to a support^2–4, micro-encapsulation^5,6, and entrapment within a membrane/film^7,8,11–20 or gel⁹. The ideal immobilization method should employ mild chemical conditions, allow for large quantities of enzyme to be immobilized, provide a large surface area for enzyme–substrate contact within a small total volume, minimize barriers to mass transport of substrate and product, and provide a chemically and mechanically robust system. Here we describe a method for enzyme immobilization that satisfies all of these criteria. We have developed a template-based synthetic method that yields hollow polymeric microcapsules of uniform diameter and length. These microcapsules are arranged in a high-density array in which the individual capsules protrude from a surface like the bristles of a brush. We have developed procedures for filling these microcapsules with high concentrations of enzymes. The enzyme-loaded microcapsule arrays function as enzymatic bioreactors in both aqueous solution and organic solvents.