Preliminary Study On Hydrogels Derived From Skin Secretion Of The Andrias Davidianus For Wound Healing

Objective: According to statistics,there are more than 4 million surgical operations in the world each year.In addition,traffic accidents and animal bites all involve the closure and healing of wounds.Traditional wound closure mainly includes surgical suture,nail and mechanical fixation,but they take a long time,and the removal of suture,nail or fixation device may cause secondary tissue damage,while the mechanical fixation device attached to the skin on both sides of the wound,such as gears,hooks and locks,has complex structure,poor comfort and cumbersome operation,which are also the reasons for its limited use.With the improvement of medical technology,the application of adhesive is considered as a clinical technique which can replace the traditional method of wound closure.However,the current commercially available adhesive can't completely meet the clinical demand.Therefore,our research group explored the feasibility and advantages of hydrogels derived from skin secretion of Andrias davidianus(SSAD)as a new adhesive material.Methods: In this study,a simple process was used to prepare the SSAD powder from skin secretion of Andrias davidianus.The powder was mixed with PBS to form a sticky SSAD hydrogel.Scanning electron microscopy,rheological behavior,FTIR spectroscopy and Raman spectroscopy were used to explore the surface morphology,viscoelasticity,protein secondary structure changes and adhesion mechanisms of SSAD hydrogels.Porcine skin was used in vitro to compare the adhesion strength and softness of SSAD hydrogel with two representative adhesives(fibrin glue and cyanoacrylate).At the same time,traditional surgical suture,cyanoacrylate and fibrin glue were used as the positive control group and hemostasis alone as the negative control group to evaluate the adhesion strength and the effect of promoting wound healing.In addition,a full-thickness skin defect model of diabetic rats was established to evaluate the ability of SSAD hydrogel to promote skin tissue regeneration and the quality of skin tissue regeneration.Finally,the biocompatibility of SSAD hydrogel was tested,including biodegradation,cell compatibility and toxic side effects on experimental animals.Results: The gelation of SSAD hydrogels became more complete with the extension of hydration time.The main functional groups for its adhesion and gelation were amino acids containing benzene rings(such as tyrosine,phenylalanine and tryptophan).Meanwhile,the existence of hydrogen bonds,S-S bonds and ?-? conjugated bonds promoted the adhesion and gelation effect of hydrogels.SSAD hydrogel had strong adhesion strength and the softness of adhesion area was consistent with normal skin tissue,which could not only shorten the healing time of skin incision but also promote the wound healing without scar.In addition,higher rates of wound closure and regenerated tissue quality were observed in the SSAD hydrogel group on full-thickness skin defects.The SSAD hydrogel achieved complete biodegradation within 3 weeks,only with mild inflammatory reaction,indicating that it had good biocompatibility.Conclusion: In summary,the SSAD hydrogel derived from the skin secretions of Andrias davidianus had strong adhesive strength,wound healing promotion,complete biodegradation and good biocompatibility,showed its wide application potential and value.