Remote control of enzymatic reaction in compartmentalized microparticles: A system for the delivery of unstable actives

Abstract

Control of biochemical reactions in living cells is based on the principle of compartmentalization, whereby the access of substrates to the active sites of enzymes is regulated by the structure of organelles with semi-permeable membranes. The present work describes the fabrication of synthetic microparticles with a similar functionality and the possibility to control substrate access to an enzyme remotely by the application of radiofrequency (RF) signals. Composite alginate hydrogel microparticles that contain iron oxide nanoparticles as local RF susceptors, liposomes that can undergo a reversible phase transition to control the release rate of encapsulated substrate, and an immobilized enzyme (laccase) that facilitates a reaction, were fabricated. Factors affecting the stability and the release kinetics have been investigated and the principle of remotely controllable on-demand enzymatic reaction in the particles has been demonstrated. This principle makes it possible to deliver unstable or reactive active ingredients that cannot be formulated into traditional dosage forms.