Study On The Preparation Of N-alkyl Chitosan Antibacterial Hemostatic Membrane

Chitosan is a kind of positively charged natural polymer.It has a wide range of source and has active chemical properties,also can be broken down by microorganism.The good biocompatibility,antibacterial activity,adsorption property and hemostatic ability made chitosan favorable in biology,medicine,chemical,food,cosmetics and other fields.Manuka honey is New Zealand’s unique honey variety and is one of the world’s two medical grade honeys with unique wound healing properties,including anti-inflammatory and antibacterial functions as well as promoting tissue growth and alleviating pain in patients.In this paper,N-alkyl chitosan with different carbon chain length and different degree of substitution(DS)was successfully prepared by alkylation modification of chitosan.The structure of the N-alkyl chitosan was characterized by FTIR,1H NMR and elemental analysis.It was confirmed that the alkyl chain has been successfully grafted to the chitosan backbone,and the degree of substitution became larger as the ratio of the raw material aldehyde to chitosan was increased.Chitosan and N-alkyl chitosan were casted to form films.The structure and properties of the membranes were characterized by scanning electron microscopy,swelling ratio detection and mechanical property test.The results showed that the membranes had regular structure and no void structure.The swelling rate,breaking elongation and breaking length decreased with the increase of the length of the grafted carbon chain.The coagulation properties of chitosan membrane and N-alkyl chitosan membrane were evaluated by thromboela-stogram(TEG)and in vitro coagulation experiments.The results showed that the in vitro coagulation effect of any N-alkyl chitosan film was better than that of chitosan film,furthermore,the blood clotting effect enhanced with the increase of the length of the grafted carbon chain and DS.Therefore,in vitro coagulation effect of N-octadecyl chitosan membrane(MCS18a)is the most significant.In order to further verify the antibacterial effect of and N-alkyl chitosan film(HMCS18a),HMCS18a was prepared by adding Manuka honey to the casting solution in order to enhance the antibacterial property of the film.MTT colorimetry and cell fluorescence staining were used to observe the cytotoxicity of the membrane.The results showed that the prepared HMCS 18a were not toxic.The antibacterial properties of HMCS18a were tested by agar plate diffusion method.The results showed that both HMCS18a had significant antibacterial effect.And the antibacterial activity increases as the concentration of honey increases.In order to investigate the spinnability of N-alkyl chitosan and the antibacterial properties of membranes,N-hexane chitosan fiber membrane(NCS6)and N-hexane chitosan honey fiber membranes(NCS6-30%)were prepared by electrospinning.The structure and properties of NCS6 and NCS6-30%fibers were characterized by SEM,contact angle and pH.The results showed that the diameter of NCS6 fibers and NCS6-30%ranged from 135 to 471 nm.The contact angle of NCS6 is 106.3±3.54,and the contact angle of NCS6-30%is 81.5±2.28.The pH values of NCS6 and NCS6-30%were within the normal skin pH range.Therefore,they can be used as dressings to contact skin directly.The results of hemolysis test and cytotoxicity test showed that NCS6 and NCS6-30%were non-toxic and could be used as medical dressings.The antibacterial performance test results showed that NCS6 and NCS6-30%had good antibacterial effect,and the antibacterial performance of NCS6 was significantly enhanced after adding honey.