Cross-linked open-pore elastic hydrogels based on tropoelastin, elastin and high pressure CO 2

Abstract

In this study the effect of high pressure CO 2 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 CO 2. Dense gas CO 2 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 CO 2 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 CO 2 were lower than the gels produced at atmospheric pressure as a result of a higher degree of cross-linking. Dense gas CO 2 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 CO 2 enabled the migration of human skin fibroblast cells 300 μm into the construct.