Study On The Preparation And Performance Of Textile-based Artificial Skin That Induces Tissue Regeneration

When the skin is injured to the dermis and even the subcutaneous tissue,there will be more serious infections and tissue defects,the self-repair process will be difficult,the healing time will be longer,and it will easily turn into a chronic wound.Therefore,external means are needed for treatment to complete the regeneration of skin tissues.The concept of tissue engineering and regenerative medicine pointed out a new development direction for repairing full-thickness wounds.One way to repair defective tissues is to use regenerative medicine to regenerate tissues in situ.At present,researchers have found that a full-thickness skin scaffold with both epidermal and dermal structures is closer to natural human skin in structure and function,and a skin scaffold with a composite structure can further enhance its application in skin tissue regeneration and repair.And existing studies have shown that fiber scaffolds can match the morphology,structure and mechanical properties of natural tissues by adjusting structural parameters to achieve the purpose of regulating cell behavior.Therefore,this project aims to design and prepare a biomimetic full-thickness skin scaffold based on textile technology,which has a multi-scale composite structure and reveals the effects of different fiber scales and different pore morphologies on skin cell adhesion and proliferation behavior.Adjust the complex structure parameters to match the cell growth environment.In addition,a large number of studies have shown that electrical stimulation has a positive effect on the function and behavior of electrically active tissues.The endogenous electric field can regulate the migration of cells to the wound and accelerate the wound healing process.Therefore,the incorporation of electroactive materials into the scaffold can stimulate the activity of fibroblasts through the transfer of charges between the scaffold and cells,thereby regulating the regeneration and repair ability of the tissue.Therefore,this subject explores a conductive artificial skin scaffold,and loads conductive materials into the above-mentioned bionic composite scaffold structure in order to prepare a conductive composite artificial skin scaffold that can effectively promote cell migration and has good biocompatibility.The main research contents of this paper include:(1)Polycaprolactone(PCL)/gelatin(Gelatin)nanostructure biomimetic epidermal structure was prepared based on electrospinning technology and chemical cross-linking method.The results showed that when the PCL ratio was greater than or equal to 50%,the fiber morphology was good;by changing the concentration of spinning solution,the average fiber diameters were 157 nm,241nm,261 nm and 483 nm after glutaraldehyde crosslinking.Cell activity experiments showed that when the average fiber diameter was 241 nm,the nanoscaffolds could promote the proliferation of keratinocytes(Ha Ca Ts),and the epithelialization could be completed on the 7th day of culture.The transmittance is2353g/m2/d,therefore,it can not only absorb excess exudate from wounds,but also prevent excessive volatilization of tissue fluid,meeting the requirements of epidermal substitutes.(2)Pure chitosan micro-porous bionic dermal structure obtained based on non-woven technology,and prepared by dipping-drying-reduction method to obtain chitosan 3D micron scaffold(CHI@r GO)loaded with reduced graphene oxide as the dermal structure.The results show that when the pore structure of the chitosan scaffold is 21.91?m,the fibroblasts appear to bridge between fibers,which is conducive to the adhesion and signal transmission between cells in the later stage of the cell.After loading conductive material,the conductivity of CHI@r GO is 5.38?10-5—9.18?10-4S/cm.Considering the biocompatibility of the dressing,when the concentration of GO dispersion is controlled to 1mg/m L,CHI@r GO has no obvious cytotoxicity,and can increase the mitochondrial membrane potential of fibroblasts(HFF-1s)and increase cell viability.The induction effect on the migration of HFF-1s is obvious,and the wound healing rate after 24 h is as high as 70.12%.At this time,the liquid absorption of the dressing is 853%,and the water vapor transmission rate is 4009g/m2/d,which is lower than the water vapor transmission rate of the bare wound of 5109g/m2/d.(3)Based on the above-mentioned bionic construction of the epidermal and dermal layers of the skin scaffold,a Schiff bond is formed between the epidermal layer gelatin and the dermal layer chitosan using a chemical cross-linking method to compound a two-layer structure.The combined epidermal layer and dermis layer maintain the original fiber morphology,the whole scaffold presents a gradient pore structure with a good appearance,the peeling strength is increased from 7.21 c N to 350 c N,and the two layers are tightly attached.The liquid absorption performance and water vapor transmission rate of the composite stent have been improved,which can prevent excessive volatilization of water in the wound site to a certain extent.In addition,the composite scaffold has good cytocompatibility,its cell proliferation rate is 90.56%,the cytotoxicity grade is 1,and there is no obvious cytotoxicity.