Electrospun Nanofibrous Wound Dressing And Scaffold Applied In Skin Wound Repair

Skin wound repair is an important clinical problem in the field of wound healing.Open wound healing is likely to cause infection and severe scars.However,the clinically wound dressings such as cotton gauze or non-woven fabrics are obviously insufficient in function.In this experiment,a double-layer fibrous membrane consisting of chitosan as the inner layer and thermoplastic polyurethane as the outer layer was fabricated by electrospinning as a wound dressing.The diversity of matrix materials was supposed to realize the versatility of the wound dressing.Morphology images verified the porous structure of the nanofiber.The evaluation of hydrophilicity,mechanical properties,and thermal properties demonstrated that the outer layer of the wound dressing was waterproof,tough,and stable at high temperatures,respectively.At last,the in vitro tests proved that the membrane has biocompatibility as a wound dressing.However,the wound dressing was limited in regulating cell behaviors.Therefore,we prepared a sandwiched photothermal polycaprolactone scaffold by electrospinning alone with coaxial electrospraying.The scaffold consisted of radially oriented fibers as the inner layer,phase change material particles made of growth factors and photothermal conversion agents as the middle layer,and random fibers as the outer layer,respectively.Exposed to the near-infrared laser,and combined with the photomask strategy,the scaffold realized spatiotemporally controllable growth factor release.We firstly tested the multi-layer structure of the scaffold through the morphology images.Then,the water contact angle showed that the scaffold was beneficial to cell adhesion after surface modification.Besides,the photothermal experiment and growth factor release study showed that the biological activity of growth factors released from the scaffold was maintained in the premise of photothermal stability.By integrating the topographic cues from scaffolds with the on-demand,sustained release of biological effectors,the migration of fibroblasts was evidently proved in vitro.Finally,using a full-thickness skin wound model in rabbits,we evaluated the efficacy of the scaffold by characterizing the wound closure area and the morphology of the newly formed tissues.Mimicking the microenvironments at different healing phases,specific types of growth factors would be triggered to release upon photo-masked laser irradiation to promote the migration of typical cells towards the wound bed and their proliferation afterwards.This project is expected to provide a new guidance for scaffold design combined with photothermal treatment to promote skin wound repair,and it has great potential in the field of tissue regeneration and controlled release.