Fabrication And Biological Evaluation Of Collagen Hydrogel With MSCs-loaded Alginate Microspheres

Objective:Based on the effect of mesenchymal stem cells in promoting wound healing,the superiority of microspheres in cell culture,and the good effect of hydrogel as wound dressing,the preparation method of MSCs-loaded alginate microspheres collagen hydrogel which can be used in the treatment of burn wound was established and improved,and the related biological evaluation was carried out.Methods:Firstly,Alginate microspheres（AMs）was prepared by Ca²⁺crosslinking,and optimized the preparation methods to obtain AMs with good roundness and uniform particle size.Then MSCs were cultured,and mixed with sodium alginate solution to prepare MSCs-loaded alginate microspheres（MSCs-AMs）.To verify the feasibility of preparing cell-carrying microspheres by spray extrusion,the survival,proliferation and distribution of MSCs in MSCs-AMs were detected by cell proliferation test and live-dead cell staining.Secondly,type I collagen was used to prepare Col gel,by adjusting the p H and temperature of collagen solution to make collagen molecules cross-linked and self-assembled.To judge whether it can meet the basic requirements of wound dressings,the basic properties of Col gel including water content,swelling ratio,contact angle,microstructure and compression properties were determined.Cell toxicity test,cell and hydrogel co-culture experiment,cell proliferation test,cell scratch test,hemolysis test,and acute toxicity test were used to determine the cytocompatibility and biosafety of Col gel.Finally,MSCs-AMs-Col gel was obtained by further wrapping MSCs-AMs with Col gel.The burn healing experiment in rats showed that MSCS-AMS-Col gel group had a higher healing rate for burn wounds.Results:AMs,with particle size of 100～200μm,uniform size and good roundness,and the surviving MSCs was successfully embedded in AMs.MTT assay and FDA-PI staining showed that MSCs grew and proliferated normally in AMs.Col gel has high water content,high water absorption,high hydrophilicity,suitable microstructure,suitable pore size,and appropriate mechanical properties.Col gel also has no cytotoxicity,can coexist with cells,promote cell migration,no hemolysis,and no acute toxicity.The experiment of burn healing in rats showed that MSCs-AMs-Col gel group had more significant effects on promoting wound healing than MSCs group and Col gel group.Conclusion:The culture of MSCs by AMs ensured the survival and proliferation of MSCs.Col gel is a material with good biocompatibility and biosafety,and its basic properties can meet the needs of wound dressings;MSCs-AMs-Col gel has better effects in the treatment of burn wounds of rats,and has the potential to be developed into a good therapeutic method for burn and scald or used in the development of wound dressings in the future.