Preparation And Properties Of Antibacterial Alginate Sodium Dressing

Due to biocompatibility and hydrophilicity,sodium alginate has been widely developed as dressings for clean wound repair.However,sodium alginate does possess the antibacterial activity,hindering its application in infected wound.To develop new generation sodium alginate dressings with superior antibacterial activity,silver nanoparticles(Ag NPs)and tobramycin(TOB)with broad spectrum antibacterial activity were in-situ grafted onto the surface of oxidized sodium alginate sponge(OSA)via solid phase modification strategy.The chemical structure,micro-morphology,porosity,antibacterial properties and biocompatibility of the two modified sponges oxidized sodium alginate-TOB(OSA-TOB)and OSA/polydopamine(PDA)/Ag NPs were systematically studied.In addition,the healing mechanism of OSA-TOB on two infected wounds were explored in-depth.The main contents are as follows:(1)OSA containing active aldehyde groups was synthesized via sodium periodate oxidation.~1H NMR analysis shown a new peak located at 8.45 ppm,attributed to the proton in aldehyde groups.Thus,OSA was successfully fabricated.Further analysis indicated that oxidation degree,molecular weight,thermal stability and dynamic viscosity of OSA show a declined inclination with the prolonged oxidation.The conductivity of OSA,however,increases gradually with the enhanced oxidation time.(2)The effects of reactive solvent on dopamine polymerization were investigated.And then sodium alginate/dopamine/nano-silver composite sponge(OSA/PDA/Ag NSs)was synthesized by adhering and reducing Ag NPs in situ with the help of PDA coating.The results show that ethanol can inhibite the polymerization of DA,but the composite sponge prepared in this system obtains good porosity and superior water absorption,which indicates ethanol can be served as ideal solvent.In vitro studies have found that200 g/m L OSA/PDA/Ag NSs,with high blood compatibility,low cell cytotoxicity,superior anti-infective activity as well as good hemostatic performance,has potential to treat infected wounds.(3)OSA-TOB conjugate was synthesized via in-situ solid state modification,and its properties were systematically studied.It is found that the graft ratio of TOB in OSA-TOB is 13.4%.In addition,OSA-TOB solution is attributed to non-newtonian fluid,showing shear thinning phenomenon.Antibacterial experiment shows that OSA-TOB can destroy the bacterial cell membrane,exhibiting superior inhibitory activity against gram-positive and gram-negative bacteria,respectively.Biological safety assessment indicates that OSA-TOB possesses good blood compatibility and can promote the growth and proliferation of L929 cells.(4)A full-thickness skin infection wound model of SD rat was established to explore the healing efficiency of OSA-TOB conjugate in infected wounds.It was found that OSA-TOB can effectively inhibit bacteria in the infected wounds,and its anti-infective activity in vivo is better than Mupirocin Ointment.On the other hand,OSA-TOB can significantly shorten the healing time of infected wounds,reduce the inflammatory,promote the synthesis and accumulation of total protein,hydroxyproline as well as collagen fiber in granulation tissue,and accelerate the formation of new blood vessels and epithelialization.Therefore,OSA-TOB possesses the function of anti-infection and healing promotion,which can be potentially applied in clinical treatment for various infected wounds.