Type 1 diabetes often leads to short-term and long-term complications which impair quality of life. Though many research groups are developing versions of an artificial endocrine pancreas (AP) system, current systems require at least one hormone delivery insertion site and at least one glucose sensor site. This complexity limits commercial viability and potential acceptance by patients. The risk of bacterial colonization and infection from the multiplicity of insertion sites merits reduction of the number of inserted devices. In this project, we propose to create a novel artificial pancreas technology that integrates into a single wearable device the following three elements: (1) an intelligent hormone delivery catheter whose outer wall contains a multi-site amperometric continuous glucose monitor (CGM), the development of which is funded elsewhere;(2) a wireless sensor module with a transceiver, battery, and data acquisition unit;and (3) a quick connect/disconnect port that attaches to the sensing catheter and to an insulin delivery tubing connector. This combination device is intended to allow more freedom of movement and increase patient comfort. We prefer the subcutaneous site over the intradermal site for sensing and hormone delivery because of a lower risk for catheter dislodgement. In order to avoid the need for perfusion- and waste fluid compartments, we prefer direct amperometry over microdialysis. In a separate project, we are using solid state design and microfabrication techniques to create the sensing catheter by placing a flat amperometric sensing array on a flexible polyimide substrate which will then be wrapped into a tube. In this application, we propose to develop the unified wearable device that will allow clinical use of the sensing catheter. This three-part device will connect to an insulin delivery line and will include an analog sensor electrical interface and a Bluetooth SMART transceiver. The combination will permit the commercial introduction of an intelligent infusion set that can connect to an insulin-only pump or an insulin/glucagon pump such as the one under development by Tandem Diabetes as funded by JDRF. This pump will likely incorporate a Bluetooth wireless interface capable of communication with our sensor module. We also propose to create an early prototype insertion device and carry out preliminary tests of the system in swine. In these tests, the three-part device with sensing catheter will be inserted subcutaneously into anesthetized pigs in order to allow (1) radiographic assessment of the catheter insertion angle and depth;(2) verification of telemetric data transmission to a remote smart phone receiver;and (3) leak-free delivery of insulin. Pig study costs will largely be covered elsewhere.
The potential for wide acceptance of artificial pancreas systems is currently limited due in part to the need for multiple device insertion sites for sensor and pump sets. Pacific Diabetes Technologies is developing a dual function catheter in which glucose sensing and hormone delivery capabilities are combined. In this application, we propose to design and create a multi- part structure that will attach to the sensing catheter, transmit sensor data to a remote receiver, and interface with an insulin delivery connector.