A BIOCHEMO-MECHANICAL SYSTEM CONSISTING OF POLYMER GELS WITH IMMOBILIZED GLUCOSE-DEHYDROGENASE

An attempt was made to construct a biochemo-mechanical system via the physical entrapment of glucose dehydrogenase (GDH) within a gel consis ting of a crosslinked copolymer of N-isopropylacrylamide and acrylic a cid. We observed that the gel with the immobilized GDH shrank when glu cose 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 i n the near vicinity of the gel phase through the enzymatic formation o f gluconic acid; the replacement of the outer medium with a fresh subs trate 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 e xcellent reproducibility. Therefore, the present immobilized system ha s the capability of converting biochemical energy into mechanical work through the swelling and shrinking of the gel support. (C) 1998 Elsev ier Science Ltd. All rights reserved.