Glucose-sensitive membrane coated porous filters for control of hydraulic permeability and insulin delivery from a pressurized reservoir

Diabetus mellitus is a serious desease that affects the health of millions of people. Since conventional insulin therapy is unable to provide good metabolic control of glucose, new systems have been developed to regulate the amount of insulin needed according to the glucose level in the blood. In the present work, a porous membrane system consisting of a porous filter grafted with a pH-sensitive copolymer and immobilized glucose oxidase has been synthesized for use as a glucose-sensitive hydraulic flow controller. The principle of this system is based upon conformational change of the graft chains in response to pH. Glucose is enzymatically converted to gluconic acid which protonates the carboxylate groups of the graft. The reduced electrostatic repulsion causes the shrinkage of the copolymer chains, opening the pores of the membrane. After fabricating a membrane pH-sensitive in the physiological pH range, glucose oxidase was immobilized on the grafted membrane. Finally, by measuring the hydraulic permeability through the composite membrane, it was shown that the prepared membrane responded rapidly to changes in glucose concentration. Incorporating the glucose-sensitive membrane, a device for a functioning bioartificial pancreas can be designed.