Although insulin has been available for the treatment of diabetes mellitus for more than half a century, the deficiencies of conventional insulin therapy for diabetic patients have, to this date, not been satisfactorily overcome by any method. The development of potential delivery systems of insulin dosage is highly important to prevent excessive fluctuations of blood sugar in the patients. There are two current approaches toward development of glucose responding insulin delivery systems: a bioengineering approach is to devise mechanical components capable of releasing insulin in amounts appropriate to varying blood-glucose requirements. A biological approach relies upon cultured, living pancreatic beta cells encapsulated to constitute an insulin delivery unit. Many efforts are underway with some success. Continual blood access from the patient to the device (be it mechanical or biological) is necessary for both approaches, which poses risks of infection and clotting with acute and prolonged use. Pancreatic transplantation in humans is not feasible at the present. The proposed study, as a chemical approach, is to synthesize stable and biologically active glycosylated insulins that are complementary to the binding sites of lectins. It has been known that these semisynthetic insulins bound to lectins release the insulin proportional to the quantity of glucose present, a natural biofeedback. We propose to encapsulate the insulin bound lectin using nondegradable and biodegradable biomedical polymers. The polymer membrane control glucose influx and, subsequently, insulin outflux which eventually optimizes the blood glucose level. In-vivo experiments, using dogs, will be performed to predict optimum blood glucose level following subcutaneous implantation and intramuscular injection of the designed systems. The results obtained would provide new concepts and criteria in the design of glucose responsing, self-regulating insulin delivery systems.