Glucose-sensitive hydrogel systems

The effect of concanavalin A on the structure of polymer hydrogels prepared via the free-radical copolymerization of acrylamide, N-(2-D-glucos)acrylamide, and N,N′-methylene-bis(acrylamide) is studied. When complexed with N-(2-D-glucos)acrylamide, concanavalin A is involved in copolymerization as a macromolecular crosslinking agent. This circumstance ensures a decrease of the degree of swelling of hydrogels in aqueous solutions with an increase in the concentration of concanavalin A in the initial monomer mixture. After the addition of glucose to an aqueous solution, the complex of concanavalin A with units of N-(2-D-glucos)acrylamide in the crosslinked copolymer dissociates and the degree of swelling of hydrogels increases considerably. Dissociation of the complex occurs at a strictly specified concentration of glucose in the solution that depend on the content of N-(2-D-glucos)acrylamide units in the copolymer. This phenomenon can be used for the controlled release of insulin previously introduced into the hydrogel through a change in the concentration of glucose in the solution.