Development of chemically crosslinked PEG-PAA hydrogels suitable for engineering of the vascularized outer retina

Abstract

To engineer a micorphysiologic system that more accurately recapitulates the vascularized outer retina suitable for evaluating AMD pathology and development of novel therapeutics. A hydrogel library based on poly (ethylene glycol) (PEG), poly-L-lysine (PLL) and poly(allylamine) (PAA) was generated using succinimide and free amine reaction chemistry. Cellular compatibility was evaluated using a rat endothelial cell line and human iPSC-derived choroidal endothelial cells generated via directed differentiation and CD31 magnetic bead immunopanning. Cell health and identity was evaluated using a series of live dead assays and immunofluorescence staining. A library of 12 synthetic, chemically crosslinked, hydrogels with tunable mechanical and degradation properties were developed. Hydrogels with a lower amine content were found to have superior endothelial cell compatibility. We hypothesize that this is due to the cell surface disrobing characteristics of the polycations presents in the gels. Hydrogels with a higher polycation concentration showed relatively poor endothelial cell compatibility. Gels with optimal compatibility were found to promote endothelial cell spreading, migration, and capillary network-like formation. In this study novel hydrogels with unique mechanical and degradation properties were generated via chemical crosslinking of PEG, PLL and PAA. Low amine hydrogels were found to be superior for promoting endothelial cell spreading, migration and vascular tube formation. To create in vitro models that more accurately recapitulate the choriocapillaris, optimized hydrogels will be used as a bioink for screen-based printing of rat and human vascular endothelial cells. This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.