Preparation And Hemostatic Properties Of Carboxymethyl Chitosan/Sodium Glginate/Shanzhiside Methyl Ester Composite Sponges

Hemorrhage often occurs in our daily life,especially in traffic accidents and operations.Uncontrolled arterial injury and massive hemorrhage pose a major threat to life and are also the main cause of casualties.Therefore,hemostatic materials are needed for treatment within an effective time.Carboxymethyl chitosan and sodium alginate have good biocompatibility,tissue compatibility,natural non-toxicity,and hemostatic functions.8-O-acetyl shanzhizide methyl ester has good hemostatic properties.It is expected that the composite materials with better hemostatic properties can be prepared by the combination of these three components.In this study,the preparation process of carboxymethyl chitosan and sodium alginate composite sponge was optimized by single factor experiment and response surface method with water absorption rate as the evaluation index.Then,carboxymethyl chitosan and 8-O-acetyl shanzhizide methyl ester were ground and blended with sodium alginate to prepare the composite sponges by freeze-induced phase separation.Structural characterization was carried out by scanning electron microscopy(SME)and Fourier transform infrared spectroscopy(FTIR)and the properties of the composite sponges such as water absorption and porosity were determined.The hemostatic activities of the composite sponges were evaluated in vitro and in vivo by using dynamic coagulation experiments,whole blood coagulation index(BCI),four indicators of blood coagulation(including PT,APTT,TT and FIB),and New Zealand rabbit hemorrhage models(including ear artery,femoral artery and hepatic).Furthermore,the hemostatic mechanism of the composite sponges was preliminarily investigated by plasma recalcification time,red blood cell adsorption and platelet adsorption experiments.Finally,the biosafety of the composite spongeswas evaluated by hemolysis,cytotoxicity and in vitro degradation experiments.The main results are as follows:(1)The optimal preparation conditions by the response surface method: the concentration of carboxymethyl chitosan is 0.5%,the mass ratio of carboxymethyl chitosan to sodium alginate is 1:2.5,and the concentration of calcium chloride is 1.5%.The sponge prepared by the optimized conditions has a good porous structure and its water absorption rate is 8020%;(2)The structure and physicochemical properties of carboxymethyl chitosan/sodium alginate/shanzhizide methyl ester composite sponges(1#,2# and 3#)were characterized.The results showed that three composite sponges of shanzhizide methyl ester had porous structure,good water absorption and high porosity.In vivo and in vitro hemostasis experiments showed that three composite sponges of shanzhizide methyl ester had significant procoagulant activity,especially the 1#composite sponge.Its BCI value was 12.2%,and platelet aggregation rate was 16%.In New Zealand rabbit hemorrhage model,the hemostasis time of ear artery,femoral artery and liver were 52.43 s,66.02 s and 18.33 s respectively.(3)The composite sponges of shanzhizide methyl ester could shorten plasma recalcification time,promote fibrinogenesis,adsorb red blood cells and adhere platelets,thus promoting blood coagulation.The results of biosafety evaluation showed that the composite sponges of shanzhizide methyl ester had no hemolysis,no cytotoxicity and good biodegradability.