Type 1 diabetes often leads to short-term and long-term complications which impair quality of life. Many research groups, including ours, are developing an artificial endocrine pancreas (AP), which combines continuous glucose sensing with automated hormone delivery. However, the complexity of current AP systems which require at least one hormone delivery catheter and at least one glucose sensor precludes current systems from commercial viability or acceptance by patients. In addition, bacterial colonization and infection at insertion sites is not unusual further emphasizing the need for reducing the number of devices that must be inserted into the patient's body. For this reason, a reduction in the number of sensing and infusion sites is desirable. In this project, we propose to create a novel artificial pancreas technology that consists of a flexible polymer-based catheter into which a continuous amperometric sensor will be integrated. In other words, this proposed device is an insulin delivery catheter that also monitors glucose continuously. This miniaturized device will allow more freedom of movement and increase patient comfort and acceptance. Because of its lower risk for catheter dislodgement, the subcutaneous location has an advantage over the intradermal location. We also believe that an amperometric sensing method is preferred over a micro-dialysis method due to the lack of a need for fluid compartments for perfusion and waste. Using advanced techniques in solid state design and micro-fabrication, we will fabricate a flat amperometric sensing array on a flexible polyimide substrate that will be wrapped around a polyimide catheter tube. A "subtraction system," using active and inactivated glucose oxidase, will be developed to avoid the effects of compounds that interfere with the continuous glucose assay. The flat sheet on which the sensing elements are placed will be automatically wrapped around a central tube to create the sensing catheter. Multichannel amplifiers will be built for laboratory testing of the sensors. A miniaturized electronic module will be developed in order to test the device in anesthetized swine. In the swine, glucose sensing accuracy from sensing catheters through which insulin is delivered will be compared to sensing catheters through which saline is delivered.
Artificial pancreas technology provides significant promise towards enabling people with diabetes to live healthier lives by enabling tight control over blood sugar levels in these patients. However, current artificial pancreas technology has limited commercial potential because the systems require multiple devices to be inserted into the patient's body including one or more glucose sensors and one or more insulin and glucagon pumps. We are proposing to develop a new dual function catheter fabricated using solid state techniques on a flexible polyimide substrate which will be both a sensing device and a hormone delivery device, thereby simplifying the AP technology and enabling a more feasible pathway towards commercialization.