Efficient scarless skin regeneration enabled by loading micronized amnion in a bioinspired adhesive wound dressing

Complete skin reconstruction is a hierarchical,physiological assembly process involving healing of the epidermis,dermis,vasculature,nerves,and cutaneous appendages.To date,few works have reported complete skin regeneration,particularly lacking vascular structures and hair follicles after full skin defects.In this study,a hydrogel derived from the skin secretion of Andrias davidianus(SSAD)that features adhesiveness was used as a bioactive scaffold to load micronized amnion(MA).The SSAD hydrogel was found to promote the migration and proliferation of amnion stem cells and human keratinocytes,as well as inhibit their apoptosis in vitro.In a rat full-skin defect model,the regeneration of skin appendages was observed at the wound area,achieving scarless healing.Transcriptome analyses further validated that SSAD could positively regulate cell migration,proliferation,and differentiation.These functions might be attributed to the abundant growth factors present in the SSAD.Synergized by the delivery of MA,SSAD loaded with the MA could achieve a significantly better skin regeneration effect than SSAD or MA used alone,providing a simple yet highly effective means to obtain complete,scarless skin regeneration,suggesting favorable potential for clinical translation.