The Application Of 3D Bioprinted Gelatin-alginate Scaffold In Full-thickness Wound Healing Mice

Objective: To investigate the biocompatibility of 3D bioprinted gelatin-alginate scaffolds,the effect of the scaffolds on the full-thickness skin wound healing on mouse back and to observe the histopathological changes during the wound healing process.Methods: 1.Porous and appropriate size gelatin-alginate scaffolds were prepared using3 D bioprinter.The rat bone marrow mesenchymal stem cells(BMSCs)were isolated and cultured in vitro and seeded on the surface of the scaffolds.And then scanning electron microscopy(SEM)was used to observe the cellular morphology on the surface of scaffolds.2.Using a murine wound model,full skin thickness excisions were created on the dorsum of 40 mice.Then,each mouse was randomly assigned to either the control group or treatment group.In the control group,the wounds were topically treated with vaseline and dressed with a thin gauze secured by an elastic bandage.In the treatment group,the wound was immediately covered with the bioactive gelatin-alginate scaffold after excision and dressed with thin gauze secured by an elastic bandage.The wounds of both groups were observed and imaged at various time points after wounding.And on day1,3,7,and 14,wound tissue samples and 0.5 cm of normal skin,from both groups,were harvested,fixed in 4% paraformaldehyde solution(p H 7.4)for 24 h,dehydrated,cleared and embedded in paraffin for histological analysis.Results: 1.The gelatin-alginate scaffolds prepared by the 3D bioprinter can be various size and contain regular holes.2.Most of the third generation BMSCs prepared by whole bone marrow adherent method show polygon-shaped and few are long spindle-shaped.Cells arranged in swirl or clumps and cell confluence can be more than 70%.3.SEM observations: Single BMSCs cell adhered well on the surface of the scaffold and presented short spindleon.4.Wound healing observation: The average healing time of the control mice was 16±1 days,while that of the treatment mice was 14±1 days.5.Histological analysis: The histopathological changes of the two groups are different in healing time and healing process.Conclusion: 1.The gelatin-alginate bioactive scaffold possesses excellent biocompati bility.2.The gelatin-alginate bioactive scaffold accelerates skin wound healing through facilitating granulation and scar tissue formation.