Preparation And Evaluation Of Biocompatible Wound Dressings

Deep skin trauma is a major health problem around the world and becomes a great burden to patients and public health care systems.Deep skin trauma needs long period to recover,so the wound dressings with high cytocompatibility and long-term antimicrobial activity are highly desired.Herein,the biocompatible and sustained antimicrobial wound dressings were developed by using antibiotic agents,ciprofloxacin HCL(CIP)and gentamicin sulfate(GS),covalent bonding to natural composite polymer matrices,carboxymethyl chitosan(CMC)and collagen(COL).The main contents and results of this thesis as follow:Three composite wound dressings,CMC-COL,CMC-COL-CIP and CMC-COL-GS,were prepared and their physical properties and biocompatibility were investigated.The water absorption ratio of wound dressings was measured in the range of 2100-3600%,the water vapor transmission rate(WVTR)was ranging from 2205.03 g/m2.24 h to 3802.15 g/m2.24 h,the tensile strength was in the range of 0.1?0.3 MPa and elongation at break was 10-15%,which could meet the requirement of ideal wound dressing.The in vitro biocompatibility test was studied by culturing the human skin fibroblasts(HSF)cells on the surface of wound dressings.The HSF cells have normal morphology and grow well,and the relative proliferation rate was more than 100%.The results indicated that the wound dressings have high biocompatibility.The antibacterial properties of wound dressings was investigated both in vitro and in vivo,and in vitro drugs release kinetics of wound dressings was measured.The results demonstrated that the antimicrobial efficacy of antibiotics has not affected by the EDC/NHS crosslinking reaction.Taking advantage of covalent interactions between antibiotics and wound dressing substrates,the wound dressings delayed the rate of drug release with complete retention of antimicrobial activity for an extended period of time(11 days).Compared with gauze group,the number of bacteria in groups of CMC-COL-CIP and CMC-COL-GS was significantly decreased on the rat wound model with infection.Moreover,the number of red blood cells and lymphocytes in these two group were lower than gauze group.The results further confirmed that the long-term antimicrobial activity of two antimicrobial wound dressings.The wound healing activity presented wound dressings were further evaluated in vivo by using animal wound model with E.coli and S.aureus infection.The results demonstrated that the antimicrobial dressings could promote the wound healing process and accelerate the reepithelialization.The collagen deposition in the wounds treated with the composite wound dressing groups reached 47%at day 6,and the blood vessel density excessed 130/mm2.In addition,numerous red blood cells were observed in the vessels'lumen.Compared to commercially available silver-based dressings(Aquacel Ag),the presented wound dressings shown superiority wound healing effects.Moreover,the wound-healing effects presented wound dressings were further demonstrated in vivo by using animal wound model without infection,which indicated the composite wound dressings could significantly accelerate skin wound healing and re-epithelialization.In summary,the finding of this thesis indicated that the prepared wound dressings have high biocompatibility,long-term antibacterial activity and rapid wound healing poperties,which meet the requirement of clinical application and have great potential application in wound healing of deep skin trauma.