Research On Preparation And Performance Of Antibacterial Hydrogel Wound Dressing

Wound dressing is a material that covers the surface of wound skin,which is used to promote wound healing.Modern medical wound dressing can not only avoid bacterial infection,but also promote the recovery of wound tissue.Hydrogel dressing is a kind of new modern dressing developed in recent years,compared with other types of dressings,its advantages include:moist tissue contact environment,good biocompatibility,the ability of absorbing wound exudates,and no adherence with wound tissue to avoid the second damage during dressing changes.Meanwhile,it can be loaded with antibacterial drugs in the hydrogel,which reinvests the hydrogel dressing with antimicrobial properties on the local wound.The aim of this paper is to prepare a biodegradable and antimicrobial hydrogel dressing for drug sustained release and wound healing.Firstly,oxidized alginate(OAlg)was prepared by a chemical modification method.and then the hydrogel was formed via the Schiff-base crosslinking reaction between oxidized alginate(OAlg)and carboxymethyl chitosan(CMCS).the mechanism of crosslinking is that the aldehyde groups of CMCS reacted with the amino groups of OAlg to form C=N bonds.To enhance the antibacterial and mechanical properties of OAlg/CMCS hydrogel,tetracycline hydrochloride(TH)loaded gelatin microspheres(GMs)were fabricated by an emulsion cross-linking method,followed by integrating into the OAlg/CMCS hydrogel to produce a composite gel dressing.The prepared OAlg/CMCS and TH/GMs were characterized and analyzed in the experiment so as to determine the best preparation parameters.In vitro gelation time,swelling,degradation,compressive modulus and rheological properties of the gel dressing(TH/GMs/Gel)prepared by the best parameters were tested.The results showed that with increasing ratios of microspheres from 10 to 40 mg/mL.the composite dressing manifested shorter gelation time and lower swelling ratios,as well as higher mechanical strength.Comparing to other formulations.30mg/mL TH/GMs/Gel showed more appropriate stability and mechanical properties,so it was more suitable for wound healing and tissue repair.In vitro drug release results showed that the composite hydrogel showed excellently sustained release effect of TH due to the double barrier mechanism of hydrogel and microspheres.Furthermore,the experiment of inhibition zones indicated intuitively that the 30 mg/mL TH/GMs/Gel had potent antibacterial effect against E.coli and S.aureus;the antibacterial rate test adequately showed that the composite hydrogel dressing had powerful bacteria growth inhibition effects against the two bacteria,and the antibacterial rate reached 99.3%and 99.5%in 24h,respectively.Therefore,30 mg/mL TH/GMs/Gel composite hydrogel dressing will have a very good application prospect in wound treatment and inhibition of bacterial infections.