Design and characterization of hydrogels of gelatin and elastin for hepatic cell culture

This work aims to demonstrate the potential of using a novel Gelatin-Elastin (GEL-ELR) hydrogel as a matrix for liver cell culture, with prospective applications for drug toxicity testing. Gelatin (GEL), through its RGD domains, promotes cell attachment, while Elastin-Like Recombinamers (ELR) provide mechanical stiffness. Furthermore, the specific ELR used in this study contains heparin-binding sites with affinity to growth factors, to attract the Hepatocyte Growth Factor (HGF) necessary for the promotion of the liver phenotype. Hydrogels with different volume ratios between the two polymers (GEL-ELR 100/0, 75/25, 50/50, 25/75, 0/100) were compared in terms of mechanical properties, Equilibrium Water Content (EWC), microstructure, heparin retention, and HGF retention. The main hypothesis tested in this project was that the presence of ELR with heparin-binding sites could increase the retention of HGF by the hydrogel. The storage modulus at shear most similar to the native liver value reported in the literature was found to be 505 Pa for GEL-ELR 50/50. The swelling ratio of the GEL-ELR 50/50 was calculated to be 5.1 ± 1.4, and microscopy images revealed that the mean pore area was 17 ± 4.64 µm². The potential of the GEL-ELR to bind heparin and HGF was evaluated by analyzing the release profiles of these molecules over a 7-day period. It was determined that the GEL-ELR 50/50 retained up to 95% of the loaded heparin and up to 77% of HGF. These results represented a very promising outcome for future cellular studies with hepatocytes.