Radiation-crosslinked scaffolds from gelatin/CM-chitin and gelatin/CM-chitosan hydrogels for adipose-derived stem cell culture

Radiation technology has been providing a useful tool to modify polymers involving the radiation crosslinking of hydrogels. In the present work, two kinds of hydrogels composed gelatin and carboxymethyl chitosan (gelatin/CM-chitosan), and carboxymethyl chitin (gelatin/CM-chitin) were prepared by the radiation crosslinking. The resulting hydrogels were freeze-dried, sterilized under gamma-ray at a sterilization dose of 25 kGy, and characterized to be utilized as the scaffolds for culturing adipose-derived stem cells (hADSCs). The physicochemical properties, biodegradability, and cytotoxicity of these scaffolds were also investigated. The results indicated that both CM-chitosan and CM-chitin much improved the swelling capacity, porosity, and pore size of the gelatin-derived scaffolds. The swelling degree of gelatin/CM-chitosan and gelatin/CM-chitin scaffolds was about 7-9 g/g after 6 hrs immerging in PBS, and their porosity was about 70-73% with pore size ranging from 100 to 300 mm. The results also revealed that the compressive modulus of gelatin/CM-chitosan and gelatin/CM-chitin was 45.6 and 66.4 kPa, respectively, which were suitable for soft tissue engineering. Both scaffolds were enzymatically biodegradable by collagenase and non-cytotoxic for hADSCs with an RGR of ~97%. Thus, the resultant scaffolds can be suitably utilized for culturing hADSC in practice to regenerate soft tissues.