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

Abstract

In this study the effect of high pressure CO(2) on the synthesis and characteristics of elastin-based hybrid hydrogels was investigated. Tropoelastin/alpha-elastin hybrid hydrogels were fabricated by chemically cross-linking tropoelastin/alpha-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 microm. 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/alpha-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 microm into the construct.