The fabrication of elastin-based hydrogels using high pressure CO2

The aim of this study was to investigate the effect of high pressure CO2 on the crosslinking of elastin-based polymers and the characteristics of the fabricated hydrogels. A hydrogel was fabricated by chemically crosslinking α-elastin with glutaraldehyde at high pressure CO2. The effects of pressure, reaction time, and crosslinker concentration on the characteristics of the fabricated hydrogels were determined. The reaction time had negligible effect on either the swelling ratio or the pore size of the fabricated hydrogels. Increasing the processing pressure from 30 bar to 150 bar resulted in a 60% increase in the hydrogel swelling ratio. The crosslinked hydrogels displayed stimuli-responsive characteristics towards temperature and salt concentration. The dense gas process facilitated coacervation, expedited the crosslinking reaction, and dramatically affected the micro- and macrostructures of pores within the sample. The results of micro-CT scan and SEM images demonstrated that pore interconnectivity was substantially enhanced for α-elastin hydrogels fabricated using high pressure CO2. Dense gas CO2 reduced the wall thickness and size of the pores and importantly induced channels within the structure of the α-elastin hydrogels. In vitro cell culture studies demonstrated that the channels facilitated fibroblast penetration and proliferation within α-elastin structures.