UC Irvine

In Type 1 Diabetes, insulin producing cells are destroyed by the immune system, resulting in unchecked glycemic conditions. Different approaches including tissue engineering and continuous analyte monitoring hold promise in providing insulin independence and glycemic control. Tissue engineering aims to transplant and protect pancreatic islets, cells responsible for secretion of insulin. One strategy is to encapsulate the islets inside alginate hydrogels. The encapsulant provides passage to glucose, nutrients and the secreted insulin, while blocking the passage of antibodies. In this study, confocal microscopy is used to study diffusional characteristics of alginate. This approach can quantitatively analyze the structural changes after exposure to physiological conditions. Using this strategy can potentially tune the structure prior to implantation to account for the upcoming in vivo changes. Another approach is to place the islets inside subcutaneous medical devices. Such devices can provide protection to the cells, however due to hypoxic conditions transplanted cells can lose function. In this study vascularization of different types of polymer devices is studied. Oxygen sensitive tubes were fabricated and placed inside devices prior to subcutaneous implantation in nude mice. Using a non-invasive optical technology oxygen partial pressure within the devices is monitored. This technology aims to create a quantitative metric to assess the state of vascularization and readiness of devices for cell insertion. Another promising technology for diabetes management and achievement of tight glycemic control is continuous analyte monitoring. In this technique, different analytes such as glucose and lactate can be continuously measured. The data collected can be used to create a mathematical algorithm that can predict upcoming glycemic changes and in conjunction with an insulin pump can automatically administer insulin. In this work, a new composite material is invented that can accommodate necessary components to detect and report the changes of analyte levels in physiological conditions. This material can be used to create different types of continuous biosensors. Importantly this composite material shows success in preserving sensitivity and activity of biosensors for long periods of storage, it shows fast responses to changes of analyte concentrations and is manufacturable in very small geometries aimed for painless insertion.