BIOCHEMO-MECHANICAL FUNCTION OF UREASE-LOADED GELS

A gel system is developed that undergoes a reversible volume phase tra nsition in response to a small amount of urea. An N-isopropylacrylamid e gel in which urease is immobilized by entrapping changes its equilib rium volume discontinuously when urea molecules are hydrolyzed by urea se causing a change in pH that alters the osmotic balance of the gel t riggering the phase transition. The system demonstrates a method of me chano-biochemical transformation where molecular recognition and bioch emical reaction are achieved by an enzyme and the macroscopic amplific ation of the reaction is carried out by a gel capable of a volume phas e transition. The work presented here is dedicated to Professor Allan S. Hoffman to honor his 60th birthday and his pioneering contribution to the science and technology of polymer gels, both as a scientist and as an educator.