Supercritical CO2 fluid-assisted cross-linking of porcine acellular dermal matrix by ethylene glycol diglycidyl ether

In addition to the cross-linker, which has an impact on the properties of the materials being cross-linked, the reaction media can impact the reaction's effectiveness. In this study, porcine acellular dermal matrix (pADM), an aggregation of collagen fibers, was cross-linked by ethylene glycol diglycidyl ether (EGDE) in supercritical CO2 fluid (sc-CO2) reaction medium (EGDE-pADM). And pADM cross-linked in ethyl alcohol medium (EtOH-EGDE-pADM) was used as control. The physicochemical properties and biocompatibility of the cross-linked pADM were evaluated. The results showed that EGDE-pADM had improved thermal stability, hydrophilicity, mechanical strength, resistance to enzymatic degradation and pore structure compared with the uncross-linked pADM and EtOH- EGDE-pADM. And the improvement of scaffolds' properties was related to the pressure of sc-CO2. The EGDE-pADM had excellent biocompatibility both in vitro and in vivo; it improved the adhesion and proliferation of L929 fibroblast cells, especially when compared with EtOH-EGDE-pADM using organic solvent, and expedited the wound healing process. These findings indicate that the reaction medium had a certain influence on the properties and cytotoxicity of the cross-linked pADM, sc-CO2 fluid was proven to be a safe and reliable cross-linking reaction medium for collagen.