In this project in the Physical Chemistry Program of the Chemistry Division, Ronald A. Siegel, of the School of Pharmacy of the University of California at San Francisco will study pulsating polymer gels. This is research destined to construct a chemical oscillator that could be used as a periodic pulsating delivery system for compounds such as hormones, antibiotics or cell specific cancer chemotherapeutic agents. A specific realization is proposed where the membrane is a copolymer of N-isopropylacrylamide (NIPA) and methacrylic acid, the substrate is glucose and the enzyme is glucose oxydase, gluconolactonase and catalase and the product is acidic protons. It is shown that the NIPA/MMA membranes are very permeable to glucose above a critical pH while below they are glucose impermeable. This is the essential feature of the pulsating mechanism. In the proposed work a chemomechanical pulsar will be constructed and the model predictions will be tested. The effects of gel composition and pH buffers will be tested, and used in the refinement of the mathematical model. Different designs will be tested to improve the versatility of the device.
