The Study Of N-succinyl-chitosan Fiber Used As A Wound Dressing

Chitosan, a kind of natural polysaccharide, is extremely rich in the nature. It hasbeen proved to have many desirable qualities, such as good biocompatibility,nontoxicity, wide bacteriostasis, biodegradability and hemostasis, so it has beenwidely developed as wood dressing, drug carrier and tissue engineering materials. Anideal medical wood dressing should have perfect qualities, such as water absorption,moisture retention, gas permeability, biocompatibility and non-toxic effect. However,due to the existence of strong intermolecular hydrogen bonding interactions, chitosanhas poor dissolving property. Chitosan, generally non-dissolved in water, can only bedissolved in a dilute acid solution, which greatly limits its application as wooddressing. In this paper, N-succinyl-chitosan (NSCS) was obtained by introducing thehydrophilic succinyl groups to free amino groups located in the2C of chitosan. Theresults showed that the water solubility of NSCS was obviously enhanced.Under the condition of absolute alcohol as solvent, different kinds of NSCS fiberwere prepared by controlling the reaction time of fibrous chitosan and succinicanhydride. The results of Infrared Spectroscopy and Solid-state13CNMRdemonstrated the successful synthesis of NSCS fiber and the introduction of succinylgroups to2C-NH2of chitosan. The degree of substitution (DS) of different NSCSfibers was determined by electrical conductivity titration method. The DS of succinylgroup was increased gradually with prolonging the reaction time. The hydroscopicityof NSCS fibers with different DS was measured by gravimetric analysis. The resultsindicated that there was a positive correlation between the hydroscopicity and DS ofsuccinyl group in NSCS. The hydroscopicity of materials was elevated gradually withincreasing the DS of succinyl group.The antimicrobial activity of chitosan and NSCS fiber material was tested withshaking culture dilution plate method. Escherichia Coli (E. coli) andStaphylococcusaureus (S. Aureus) are tested. The results indicated that the unmodified chitosan fiber can restrict90%E. coli, and antimicrobial against S. Aureus was about80%. However, the NSCS fiber had obvious inhibiting effect on both bacteria, thebacterial inhibition was more than99%. The antimicrobial activity of chitosan wasincreased after modified with acid anhydride.The biocompatibility of chitosan and NSCS fiber material were studied byhemolysis experiments and MTT method. All the hemolysis rate of fiber materialrespectively was less than3%. The result indicated that the NSCS fiber materials weresatisfied with the standard for hemolysis of medical materials. The hemolysis ratewould increase with the increase of degree of substitution. In the cytotoxicityexperiment, the relative survival rate of the mouse embryonic fibroblast (MEF) andhuman skin fibroblasts (HSF) cultured in the low concentrations of materials wasmore than80%, respectively. The result indicated that the cytotoxicity of this kind offiber material was slightly.The NSCS fiber with optimal DS was selected for evaluating its wood healingcapacity. In this experiment, SD mice were used as the wood model and the oneshealing with medical gauze were set as blank control group. The results showed thatNSCS fiber had the capacity to promote wood healing. Meanwhile, inflammation washardly observed in tissue sections.In summary, N-succinyl-chitosan fiber material has water absorption, moistureresistance, breathability, antibacterial activity, biocompatibility, and it can alsopromote wound healing. N-succinyl-chitosan fiber is applicable as an ideal wounddressing.