A biochemo-mechanical system consisting of polymer gels with immobilized glucose dehydrogenase

Abstract

An attempt was made to construct a biochemo-mechanical system via the physical entrapment of glucose dehydrogenase (GDH) within a gel consisting of a crosslinked copolymer of N-isopropylacrylamide and acrylic acid. We observed that the gel with the immobilized GDH shrank when glucose as the substrate was added into an outer medium together with NAD⁺ as the coenzyme. This was due to a decrease in the pH within and in the near vicinity of the gel phase through the enzymatic formation of gluconic acid; the replacement of the outer medium with a fresh substrate solution to remove gluconic acid returned the gel to its initial volume through swelling, although it started to shrink again within a few minutes. These swelling and shrinking cycles were repeated with excellent reproducibility. Therefore, the present immobilized system has the capability of converting biochemical energy into mechanical work through the swelling and shrinking of the gel support.