 Current treatment of in type 1 diabetes comprises the measurement of glucose in capillary blood obtained by fingersticking and administration of exogenous insulin in the form of a subcutaneous bolus injection or subcutaneous infusion. This treatment could be simplified if there were a stable ratio between blood glucose concentration and tissue glucose level at the site of insulin delivery so that tissue glucose levels could be used to estimate blood glucose levels, thereby circumventing the need for fingerstick blood glucose monitoring. 