(194ad) Toroidal-Spiral Particles for Islet Encapsulation

The design of cell encapsulation systems for treatment of chronic diseases like type I diabetes serves as an effective mechanism to deliver therapeutic solution from insulin producing cells, such as beta cells or islets of Langerhans. Current cell therapy approaches involving Islets of Langerhans encapsulation seek optimal immunoprotection, nutrient and oxygen transport and simultaneously robustness and retrievability. We aim to develop a system using polymeric self-assembled toroidal-spiral particles (TSPs) to encapsulate therapeutic cells. Formation of the TSP is through a self-assembly process by single drop sedimentation or drop interaction, which is further solidified by photo-initiated cross-linking of the polymeric matrix.^1,2 Resembling a toroid and exhibiting internal channels that provide large surface area to volume ratio, TSPs have served as a delivery system for proteins and small molecules allowing for dual drug encapsulation with independent release pathways.³ TSPs with tunable empty channel were designed and generated for cell encapsulation. Viability and functionality of encapsulated human islets of Langerhans in the TSPs are studied. Transport of insulin, glucose, and antibodies were characterized. The individual TSP can be injected through a catheter. A retrievable device was also produced by an array of TSPs attached on a thin polymeric membrane.

1. Sharma, V., Szymusiak, M., Shen, H., Nitsche, L. C. & Liu, Y. Formation of Polymeric Toroidal-Spiral Particles. Langmuir 28, 729–735 (2012).
2. Szymusiak, M., Sharma, V., Nitsche, L. C. & Liu, Y. Interaction of sedimenting drops in a miscible solution – formation of heterogeneous toroidal-spiral particles. Soft Matter 8, 7556–7559 (2012).
3. Sharma, V. et al. Toroidal-Spiral Particles for Codelivery of Anti-VEGFR-2 Antibody and Irinotecan: A Potential Implant to Hinder Recurrence of Glioblastoma Multiforme. Biomacromolecules 15, 756–762 (2014).