Preparation And Properties Of Alkylated Chitosan-based Fast Hemostatic Sponge

Uncontrollable hemorrhage is one of the main causes of death in battlefields and accidents.Most of the fast hemostatic products on the market are expensive at present,and there are some shortcomings such as unstable hemostatic effect and easy residue,which can cause inflammatory to patients.Therefore,it is urgent to develop a safe and efficient fast hemostatic material.N-alkylated chitosan(N-CS)and graphene oxide(GO)have attracted extensive attention because of their good hemostatic and breathable properties.However,the monotonous composition of N-CS has poor hydrophilicity,and the free GO has cytotoxicity and hemolytic activity.To overcome this problem,N-alkylated chitosan/gelatin(GEL)/polyvinyl alcohol(PVA)composite sponge were firstly prepared in this paper,then GO was introduced to prepare GO/N-CS/GEL/PVA composite hemostatic sponge(N-CSGS)coupled with the study of its physical chemical properties and hemostatic properties respectively.The experiments were listed in below:1.N-hexyl chitosan and N-dodecyl chitosan with three degrees of substitution(5%,10%and 30%)were prepared by reductive amination.In vitro coagulation tests showed that the whole blood clotting time of N-CS was significantly shorter than that of chitosan(100.13±5.52 s).Among them,chitosan grafted with 30%dodecyl chain(N-CS 12a)had the shortest whole blood clotting time(70.66±4.48 s).Therefore,N-CS 12a was compounded with gelatin and polyvinyl alcohol to prepare N-CS/GEL/PVA composite sponge by freeze-drying method.Taking water absorption as an index,the best preparation conditions of composite sponge were determined by single factor experiment:the total concentration of the solution was 2%,mN-CS:mGEL:mPVA=2:2:1,glycerol addition was 1%,glutaraldehyde addition was 0.5%.Under these conditions,the water absorption of the composite hemostatic sponge was 28.25 g/g.2.Graphene oxide was prepared by improved Hummers method.Under the optimized preparation conditions,GO of 0 mg/mL,25 mg/mL,50 mg/mL,75 mg/mL and 100 mg/mL were added to N-CS/GEL/PVA sponge,and GO/N-CS/GEL/PVA composite sponge(N-CSGS)was prepared,which were named as N-CSGSO、N-CSGS1、N-CSGS2、N-CSGS3 and N-CSGS4 sponges respectively.All N-CSGS sponges showed good liquid absorption capacity,mechanical properties and hemostatic properties.With the increase of GO addition,the properties of N-CSGS sponge were obviously improved.Among them,the N-CSGS4 sponge had the best comprehensive performance,its porosity was as high as 93.86%,its water absorption rate was 34.72 g/g with good stability.Its degradation rate in vitro was only 70%after 45 days.In addition,the hemolysis rate of N-CSGS4 sponge was lower(0.39%<<5%),and its coagulation time in vitro was shortened to 41.35 s compared with that of the common medical gauze group(118.67 s).The above experimental results showed that N-CSGS4 composite sponge is expected to be a safe and rapid hemostatic material.