(192b) Effect of Crosslink Density On Protein Diffusion Through Peg Hydrogels with Permeability Gradients

Tugba Bal, Burcu Kepsutlu, Seda Kizilel

Koç University, Chemical and Biological Engineering, 34450, Istanbul, Turkey

Transplantation of cells within PEG hydrogel scaffolds as effective immunoisolation barriers is becoming increasingly important strategy for tissue engineering and regenerative medicine. The design of effective immunoisolation barriers for cell transplantation requires characterization of protein diffusion through these networks with crosslink density gradients and effect of changes in the network structure to protein diffusivity. Efforts have been limited towards creating immunoisolation barriers and characterization of transport of proteins from synthetic PEG hydrogels with crosslink density gradients. In this study, PEG hydrogels of different crosslink density and permeability gradients were formed via surface initiated photopolymerization of PEG monomers with different molecular weight and prepolymer concentration, and the diffusion of model proteins with various molecular weights was observed through PEG hydrogel scaffolds. Experimental swelling measurements and theoretical crosslink density predictions from our mathematical models were also used to obtain correlation between experimental and theoretical swelling for these synthetic PEG hydrogels. Fibroblasts encapsulated in PEG hydrogels of differing permeability properties, and cell survival was examined for each condition. The results confirm that synthetic PEG hydrogels with permeability gradients are promising for controlled release of bioactive molecules and covalent incorporation of ligands to support cell viability.