Preparation Of An Antibacterial Dressing For Simultaneous Delivery Of Polyhexamethylene Biguanide And Platelet-rich Plasma,and Evaluation Of The Dressing’s Ability To Promote Infected Skin Repair

Backgrounding:The integrity of healthy skin plays a vital role in maintaining the physiological homeostasis of the human body.The skin is the body ’s largest organ system.It plays a key role in preventing mechanical force and infection,fluid imbalance and thermal imbalance.At the same time,its flexibility makes it possible to perform joint functions in certain areas of the body,and to fix the palm or prevent the movement of the soles of the feet through friction.Many cases can lead to inadequate wound healing and require medical intervention.Chronic conditions such as diabetes or peripheral vascular disease can lead to impaired wound healing.Loss of skin organ function can occur after acute trauma(such as avulsions or burns),leaving microorganisms vulnerable to infection,thermal imbalance and loss of body fluids.Various medical methods and treatments are involved in the cascade of different processes of wound healing.If the injury is minor,the healing time will be short.When less tissue is injured,the healing time may be even shorter.In minimally invasive surgery,for example,this reduces soft tissue damage and post-operative morbidity.Topical growth factors and incisional drainage can optimise the cellular and molecular environment of the wound,thereby reducing healing time by altering inflammation and speeding up healing.Slow wound healing caused by bacterial infection is a key clinical challenge.Wound infections can cause delayed wound healing and pain,but can also lead to more serious complications,such as tissue necrosis and even sepsis,which can lead to loss of tissue,limbs or life.Antibacterial wound dressings have become a viable option to reduce wound bacterial colonization and infection to improve the healing process.Objective:We designed a multifunctional dressing that can simultaneously resist infection and promote wound healing,and simultaneously deliver PHMB and PRP.Subsequently,we verified the biocompatibility,antibacterial effect of the composite dressing and the actual effect of the dressing in the full-thickness skin infected wound of rats,providing a new direction for the study of accelerating wound healing and multifunctional hydrogel dressings.Methods:1.The PVA / PHMB / PRP composite dressing was assembled by hydrogen bonds was prepared by repeated freeze-thaw method.2.The morphology and characterization of the dressing were detected by XRD,FTIR,SEM and rheological measurement.3.In vitro experiments,the release of growth factors was detected by enzyme-linked immunosorbent assay,the biocompatibility of the composite dressing to L929 fibroblasts was detected by MTS assay,and the antibacterial effect of the hydrogel on Gram-negative bacteria(Pseudomonas aeruginosa)and Gram-positive bacteria(Staphylococcus aureus)was detected by bacteriostatic ring method.4.The wound models of Pseudomonas aeruginosa and Staphylococcus aureus infection were established on the back of SD rats,and the therapeutic effect of the composite dressing was detected by wound closure rate,HE staining,Masson staining and immunohistochemistry.Results:1.The hydrogel was prepared by repeated freeze-thaw cycles through a simple and environmentally friendly procedure without chemical crosslinking agent.Characterization studies revealed the excellent stability of these composite hydrogels.2.The antibacterial ring experiment showed that the hydrogel containing PHMB had strong antibacterial effect.MTS and ELISA results showed that hydrogels containing PRP showed low cytotoxicity and significantly stimulated the proliferation of L929 fibroblasts.3.The results of animal model showed that the wound closure rate of PVA / PHMB /PRP composite dressing group was faster,HE staining showed lower inflammation level and higher degree of epithelization.Masson staining showed that collagen deposition was abundant and neatly arranged.Immunohistochemistry showed that TGF-β and CD31 maintained high levels of expression,and IL-6 expression was low.Conclusion:1.We effectively combined the antibacterial ability of PHMB and the ability of PRP to promote wound healing into a biocompatible PVA-based dressing to create a multifunctional hydrogel wound dressing.2.Biocomposite dressings not only protect bioactive molecules derived from PRP,but also ensure their stable release in the wound,thus avoiding rapid degradation associated with typical PRP gels.3.PRP composite dressing could reduce inflammation,promote epithelial formation,enhance collagen and angiogenesis,and restore skin appendages.Therefore,PVA /PHMB / PRP composite dressing can promote wound healing and skin function recovery.