Preparation Of 3D Composite Scaffolds Based On Porcine Acellular Dermal Matrix For Skin Wound Healing

The use of decellularized extracellular matrix(d ECM)alone or in combination with other materials,utilizing techniques such as electrospinning,hydrogelation,or 3D bioprinting,to prepare tissue-engineering composite scaffolds with specific physical and chemical properties,represents a novel research approach and application strategy.This paper focuses on the study of Porcine Acellular Dermal Matrix(PADM),a biologically active material,and designs two types of 3D composite scaffolds with antibacterial and conductive functions for skin wound repair.The specific research content was as follows:1.The prepared PADM powder was mixed with polycaprolactone(PCL)and used to prepare PCL-PADM electrospun membranes using electrospinning technology.The fiber morphology was observed using SEM,and the mechanical properties were assessed using a universal material testing machine.The results showed that the fibers were randomly arranged and the surface was porous,with excellent mechanical performance.The electrospun membrane was expanded into a 3D PCL-PADM scaffold by in-situ gas foaming method.The thickness of the scaffold changed with the expansion time and PADM content,indicating that the scaffold thickness is adjustable.A 3D PCL-PADM-10%/ε-PL scaffold was further obtained by grafting antibacterial peptide ε-PL onto the scaffold.Compared with 2D PCL-PADM-10%(504.8%),the swelling ratios of 3D PCLPADM-10% and 3D PCL-PADM-10%/ε-PL were significantly increased,to 1321.4%and 1513.3%,respectively,which improved hydrophilicity and promoted cell adhesion and proliferation on the scaffold.The cytotoxicity of the scaffolds on L929 and 3T3 cells was analyzed using the MTT method.The antibacterial experiments showed that the 3D PCL-PADM-10%/ε-PL scaffold had excellent antibacterial ability.The composite scaffolds were used to repair full-thickness skin injury,the 3D PCL-PADM-10%/ε-PL scaffold had better anti-inflammatory effects and the fastest healing time.2.OHA,APADM,and DA@Fe were prepared and characterized using FTIR,HNMR,and UV-Vis analysis.PEDOT:PSS and DA@Fe were loaded into OHA/APADM to prepare conductive hydrogel composite scaffolds(OHA-APADMs).SEM was used to observe the microstructure of OHA-APADMs in different groups,and the results showed that the addition of APADM contributed to an increase in pore size.According to the compression stress-strain and rheological characterization,the results showed that OHAAPADMs was a pseudoplastic fluid,and the higher the content of APADM,the higher the crosslinking degree,strength,and stability of OHA-APADMs.The water absorption capacity indicated that OHA-APADMs had high swelling rate.Four-Point Probes Resistivity Measurement System was used to analyze the electrical properties of OHAAPADMs,and the conductivity was between 0.207-0.322 S/m.Cell toxicity and livedead staining showed that OHA-APADMs had good biocompatibility,and cell scratch experiments showed that OHA-APADMs could induce cell migration,with OHAAPADM-2 being the most effective.An SD rat full-thickness skin injury model was established to evaluate the healing effect of OHA-APADM-2 and ES on the wound.The tissue sections of the wound were collected for H&E,Masson’s staining,and immunofluorescence staining(CD31,TNF-α).The experimental results showed that OHA-APADM-2 combined with ES had a significant effect on skin tissue regeneration,and had further potential for clinical application as a tissue-engineered skin repair scaffold.