The purpose of this study is to use the USS Virginia Closed-Loop system for overnight insulin delivery in adults with Type 1 Diabetes (T1DM) in an outpatient setting to evaluate the system's ability to significantly improve blood glucose levels. This protocol will test the feasibility of "bedside" closed-loop control - an approach comprised of standard sensor-augmented pump therapy during the day using off-the-shelf devices and overnight closed-loop control using experimental devices in an outpatient setting. The rationale for this study is as follows: we anticipate that closed-loop control may ultimately be adopted by patients with T1DM in a selective manner. Patient may choose to start using these systems for overnight control only, e.g. to alleviate the well documented fear of hypoglycemia while asleep. To test this paradigm of "bedside" closed-loop control, subjects will be studied with continuous glucose monitoring (CGM)-augmented usual pump therapy during the day followed by overnight use of USS Virginia Closed Loop Control.