Cross-linked open-pore elastic hydrogels based on tropoelastin, elastin and high pressure CO2

In this study the effect of high pressure CO2 on the synthesis and characteristics of elastin-based hybrid hydrogels was investigated. Tropoelastin/α-elastin hybrid hydrogels were fabricated by chemically cross-linking tropoelastin/α-elastin solutions with glutaraldehyde at high pressure CO2. Dense gas CO2 had a significant impact on the characteristics of the fabricated hydrogels including porosity, swelling ratio, compressive properties, and modulus of elasticity. Compared to fabrication at atmospheric pressure high pressure CO2 based construction eliminated the skin-like formation on the top surfaces of hydrogels and generated larger pores with an average pore size of 78 ± 17 μm. The swelling ratios of composite hydrogels fabricated at high pressure CO2 were lower than the gels produced at atmospheric pressure as a result of a higher degree of cross-linking. Dense gas CO2 substantially increased the mechanical properties of fabricated hydrogels. The compressive and tensile modulus of 50/50 weight ratio tropoelastin/α-elastin composite hydrogels were enhanced 2 and 2.5 fold, respectively, when the pressure was increased from 1 to 60 bar. In vitro studies show that the presence of large pores throughout the hydrogel matrix fabricated at high pressure CO2 enabled the migration of human skin fibroblast cells 300 μm into the construct.