Preparation Of Quaternized Chitosan And Its Application In Wound Healing

Chitosan(CTS) is a natural alkaline macromolecular compound, which have excellent biodegradability, good antimicrobial property and biocompatibility. Because of its poor water dissolution property, the application of chitosan is limited. The quaternization of chitosan is one of the important way to improve its water solubility and antibacterial property. Degree of quaternization(DQ) and the chain length of quaternary ammonium cationic group(CL) are two significant factors to the antibacterial property of the quaternized chitosan(QC). At present, there are few reports about the effect of DQ and CL on the antibacterial property of QC. Moreover,the application researches of quaternized chitosan is focus on the sterilization in vitro, and few works on the application of quaternized chitosan in vivo, such as the wound healing, etc..In this study, various quaternized chitosan with different DQ were prepared from chitosan and glycidyl trimethyl ammonium chloride(or glycidyl triethyl ammonium chloride) by using different molar ratios of reactants. The structures of glycidyl trimethyl ammonium chloride modified chitosan(GTMA-CTS) and glycidyl triethyl ammonium chloride modified chitosan(GTEA-CTS) were characterized by FT-IR and1H-NMR. The antibacterial properties and mechanism of quaternized chitosan against S. aureus, E. coli, P. aeruginosa and C. albicans were studied by plate counting method. Moreover,the impact of DQ and CL on the antibacterial property of quaternized chitosan has been discussed. In addition, the cell cytotoxicity of quaternized chitosan with various DQ against L929 cell was researched by agar diffusion method, and the influence of DQ on the cytotoxicity of quaternized chitosan was studied. Taking the inhibitory rate, cell cytotoxicity and cost into consideration, the GTMA-CTS with the DQ of89.16% was selected as the study subject to research the properties of quaternized chitosan, such as the biological properties and the ability to accelerate wound healing process. The results as follow:(1) By changing the reactants molar ratio of GTMA, GTEA with CTS, soluble GTMA-CTS and GTEA-CTS with different DQ were successfully obtained from chitosan, and the DQ of QC increase with increment of GTMA and GTEA.(2) The results of antibacterial experiments show that the fungal antibacterial ability of quaternized chitosan is stronger than the other bacteria we used, and the antibacterial effect on S.aureus is generally stronger than E. coli and P. aeruginosa. Furthermore, the inhibition rate of GTEA-CTS increase with the increment of the DQ when DQ is less than 100%, but the inhibitory ability of GTMA-CTS remain stable at about 100%. When DQ is over 100%, theinhibition rate of GTEA-CTS change to about 100%, while the inhibition rate of GTMA-CTS actually decrease. Thus, DQ play a major role on the effect of the antibacterial properties when DQ is low, but the length of chain start to play a leading role at high DQ.(3) Agar diffusion test illustrate that the cell toxicity of the QC are 1 level, the cell cytotoxicity of QC is not apparent. The result of hemolysis test show that the hemolysis ratio of1 mg/m L GTMA-CTS(89.16%) is up to national standards. In addition, the acute dermal and oral toxicity of GTMA-CTS(89.16%) is low, and have no irritation to the intact or damaged skin of rabbits. The above results indicate the GTMA-CTS(89.16%) has excellent biocompatibility.(4) The result of wound healing experiment demonstrate that 1 mg/m L solution of GTMA-CTS(89.16%) can effectively eliminate the bacteria in wound, accelerate the healing process of infected wound, and produce no toxic and side effect. It could be expected that the GTMA-CTS(89.16%) was hopefully used in the therapy of infected wound in the future.