Organic-inorganic nHA-Gelatin/Alginate high strength macroporous cryogel promotes bone regeneration

Macroporous cryogel has the advantages of nutrient exchange and cell growth, and is an ideal material for tissue regeneration. In order to strengthen the machenical properties of cryogel for the widely use, a high strength gelatin/sodium alginate/nano hydroxyapatite (nHA) porous cryogel (GA-HA cryogel) was prepared by a simple freeze-thaw process. The mechanical strength of GA-HA cryogel increased significantly with the increase of nHA content. In vitro studies showed that GA-HA cryogel had good biocompatibility and no obvious cytotoxicity to MC3T3-E1 cells. The results of alkaline phosphatase activity assay and osteocalcin immunofluorescence staining showed that GA-HA1 porous hydrogel system could significantly increase the expression of MC3T3-E1 alkaline phosphatase and osteocalcin when the content of nHA was 1 ​%. In addition, porous GA-HA cryogel showed good performance in promoting bone regeneration in rat skull defect model. Therefore, the high-strength double network cryogel prepared in this study can provide new applications in bone repair and tissue regeneration.