Release Of Tannic Acid And AFGF From Layer-by-layer Films For Enhanced Infected Dermal Wound Regeneration

Normal wound healing is an orderly process,mainly involving several phases including hemostasis,inflammation,proliferation and remodeling.However,the orderly processes may be disturbed after the bacterial infection preventing the tissue restoration and hindering the wound healing process.In order to effectively treat infected wounds,wound dressings should show excellent antibacterial activity and cellular behavior,which can stimulate angiogenesis and tissue regeneration.At present,silver coated dressings show excellent antibacterial effect,but their potential cytotoxicity and high price greatly inhibit their further application.Therefore,in this study,we chose tannic acid(TA)as an antibacterial agent.Meanwhile,growth factors such as acid fibroblast growth factor(aFGF)can effectively promote cell proliferation and tissue regeneration,but it is easy to inactivate and lose.Because of these shortcomings,the combination of growth factors and antibacterial drugs have never obtained ideal outcome of wound healing.Hence,we prepare a layer-by-layer self-assembly(LbL)film dressing by using layer-by-layer self-assembly technology,which fabricate from TA and Polyvinylpyrrolidone(PVP),at the same time,aFGF is loaded in it,so as to establish a novel drug delivery system.Due to the dynamic nature of hydrogen bonding,when in wet conditions,the LbL films disassemble gradually and thus release TA and aFGF.This method is flexible to control the load of TA and aFGF through the number of self-assembled layers,and also can maintain the activity of aFGF to the greatest extent.In vitro and in vivo studies show that the LbL film dressings have the ability to significantly inhibit the growth of S.aureus and E.coli,promote cell proliferation and migration,promote angiogenesis,and then promote wound healing.These results indicate that the LBL film is a potential candidate for dressing.