Diabetes mellitus is a leading cause of morbidity and mortality in the United States. In addition, this medical condition disproportionately affects individuals from minority ethnic groups as well as older individuals. Although previous microneedle-based insulin delivery and glucose sensing efforts have envisioned microneedle-tissue contact for extended periods of time, no study to date has sought to optimize microneedle design in terms of biological, chemical, and mechanical properties for extended use within a wristwatch form factor device that is capable of 200 skin penetration events.
The PI will partner with a leading US-based manufacturer of glucose meters, Prodigy Diabetic Care, to develop a comprehensive research, education, and outreach program that involves rapid prototyping of microneedles for use in insulin delivery as well as glucose sensing. The main benefit of the proposed collaborative research program is intensive access for the PI and the graduate researcher to the state-of-the-art equipment at Prodigy Diabetic Care, including equipment for preparing glucose oxidase, determining the consistency of glucose oxidase, determining blood glucose levels, preparing insulin patches, testing electronics, and designing meter containers. Five hundred square feet of space at Prodigy Diabetic Care will be devoted to the proposed GOALI effort. The research objective of this GOALI proposal is to apply a rapid prototyping method known as two photon polymerization and a recently-developed class of materials known as zirconium oxide hybrid materials to create hollow microneedles with appropriate chemical, biological, mechanical, and functional properties for extended use in a wristwatch form factor device.
The outcomes of the project include (a) formation of zirconium oxide hybrid material structures with small-scale features using two photon polymerization, (b) formation of stiff polyglycolic acid microneedles using injection molding and drawing lithography, (c) formation of an acrylate-based polymer hollow microneedle using two photon polymerization and intergration of this microneedle with a biosensor, (d) use of molecularly imprinted polymers for protein detection, and (e) use of piezoelectric inkjet printing to apply drugs to the surfaces of microneedles. We created microscale structures out of a zirconium oxide hybrid material using two photon polymerization. Cell interactions with these structures were evaluated using in vitro studies. In addition, use of piezoelectric inkjet printing to deposit drugs (e.g., drugs that show poor solubility in water) on the surfaces of microneedles was examined. For example, miconazole was deposited on the surfaces of biodegradable microneedles using piezoelectric inkjet printing. Furthermore, stiff and sharp polymer microneedles were made out of a biodegradable polymer. Use of hydrogel-based molecularly imprinted polymers for protein detection was considered. Programs at the North Carolina Museum of Natural Sciences were developed by the principal investigator to facilitate interactions between scientists and young people; results from the program were disseminated at a museum event. Results from the program were also disseminated via several journal articles as well as conference presentations.
