Autonomous gel enzyme oscillator fueled by glucose: Preliminary evidence for oscillations

A novel prototype gel oscillator that functions by dissipating the chemical energy of glucose by an enzyme-mediated reaction is proposed. The product of the reaction modulates the degree of swelling and hence the permeability of a poly(N-isopropylacrylamide-co-methacrylic acid) gel membrane which in turn regulates the flow of substrate to the enzyme. No external energy is required aside from the chemical energy of glucose present externally at co nstant concentration. A negative chemomechanical feedback loop is establish ed which, coupled with hysteresis in the membrane permeability characterist ics, produces pulsing oscillations. In this study, we introduce a simple mo del which provides guidelines for experimental design, and report prelimina ry experimental evidence for oscillation. Application of this prototype sys tem to the episodic delivery of drugs and hormones is envisaged. (C) 1999 A merican Institute of Physics. [S1054-1500(99)00102-0].