Development of accurate continuous glucose monitoring devices is critically important for the maintenance of strict glycemic control without increasing the risk for hypoglycemia and for the successful implementation of an artificial pancreas. Glucose binding protein-based (GBP) continuous glucose monitors offer several potential advantages over commercially available glucose oxidase based sensors. Unlike glucose oxidase based sensors, GBP sensors do not require establishment of an equilibrium reduction/oxidation reaction and are not as susceptible to interference from other compounds because they are engineered to recognize only glucose. As a result, GBP-based glucose sensors are exceptionally accurate at low blood glucose levels and have a faster warm-up time than glucose oxidase based systems. The principal idea of this proposal is to evaluate the accuracy and performance of a second generation glucose binding protein-based continuous glucose monitor (GBP CGM) developed by BD Technologies in subjects with type 1 diabetes, with emphasis on warm-up period after insertion, accuracy in hypoglycemic and hyperglycemic ranges, and lag time over a 24 hour period of sensor use. In order to accomplish this, the investigators will conduct a clinical trial consisting of 25.5-hour studies involving 15 subjects, each wearing one active and one mock (no GBP) device simultaneously during meals and induced hypoglycemia to observe a wide range of glucose values. The investigators envision that the glucose binding protein-based continuous glucose monitor will demonstrate minimal warm-up time after insertion, overall accuracy comparable to commercial glucose oxidase sensors with excellent performance in the hypoglycemic range and a nominal lag time to sensing a change in blood glucose.