The Wearable Artificial Endocrine Pancreas with a Needle‐ Type Glucose Sensor: Perfect Glycemic Control in Ambulatory Diabetics

Abstract

Abstract We have succeeded in miniaturizing a glucose monitoring system into a needle type which preserves the characteristics suitable to apply in a wearable closed‐loop control system. The wearable artificial endocrine pancreas (12 times 15 times 6 cm, 400 g) consists of the sensor, a microcomputer system which calculates insulin and glucagon infusion rates and a 2‐syringe driving system. When glucose monitorings were attempted by a needle‐type glucose sensor inserted in subcutaneous tissue of the forearm or abdomen of healthy and diabetic volunteers, these results were around 10% lower than blood glucose concentrations, but high correlation between them was observed in the range of49–388 mg/dl. Perfect glycemic controls were established by infusing insulin intravenously or even subcutaneously in response to measured glucose concentrations on a moment‐to‐moment basis in diabetics for a period of several days. By comparing the glycemic controls with those obtained in each patient with intensified multiple insulin injection regimes, the superiority of feedback control with the system was clearly demonstrated. These data might indicate the feasibility of long‐term glycemic control in ambulatory diabetic patients with a wearable closed‐loop glycemic control system.