(720c) Development and Evaluation of Targeted Polycaprolactone Nanocapsules for Selective Delivery to Pancreatic ?-Cells in Type 1 Diabetes

Type 1 diabetes (T1D) is a chronic autoimmune condition marked by the immune-mediated destruction of pancreatic β-cells. While research into the protection and proliferation of β-cells has advanced, the lack of therapies that selectively target β-cells has hindered therapeutic efficacy and progress in developing new treatments for T1D. To circumvent this problem, we have developed a novel polycaprolactone (PCL) nanocapsule (NC) that can be coated with interchangeable targeting ligands for β-cell targeted drug delivery. We hypothesize that NCs coated with a targeting ligand will selectively target human islet β-cells. Initially focusing on Exendin-4 (Ex4), a GLP1 agonist, conjugated to hyaluronic acid (HA) for β-cell targeting, we subsequently explored ectonucleoside triphosphate diphosphohydrolase 3 (ENTPD3) antibody targeting due to its specificity for human β-cells. Our NCs averaged 258.3 nm +/- 5.46 nm in size. Coating NCs with 0.2 mg/mL fluorescently labeled HA and washing via centrifugation revealed 0.0022 mg/mL HA remained on the NCs, demonstrating stability of NC coating with peptides. NCs were loaded with Cy5 fluorophore and coated with ENTPD3 or HA-Ex4 and HA alone or guinea pig IgG antibody as negative controls. These NCs were used to treat cadaveric human islets for 24- 48-hours and islets were subsequently stained with NucBlue for cell nucleus identification and FluoZin-3 for β-cell identification. NC+ cells were manually counted in ImageJ by locating FluoZin-3 positive cells with co-localized Cy5 signal, indicating NC internalization. We found HA-Ex4 and guinea pig IgG coated NC uptake in 5% and 7% of insulin+ b-cells respectively, while ENTPD3-coated NCs showed uptake in 17% of images. Additionally, NCs injected via tail vein into NOD-SCID mice were shown to target the pancreas in vivo, where NCs coated in HA-Ex4 were enriched in β-cells by ~400% compared to HA only coated NCs 24h post injection (p=0.014). Pancreas specific uptake of NCs was confirmed by IVIS imaging. Our results indicate that NCs can be coated with targeting peptide for specific delivery to β-cells in vitro and in vivo. The results from this study present a novel strategy for selective delivery of therapeutic cargo to β-cells, that may lead to novel treatments for T1D.