Preparation And Properties Of Quaternized Carboxymethyl Chitosan As Polymer Hemostatic Coating

Hemostatic materials play a key role in the emergency control of bleeding after trauma.For such medical devices injected into the body with a fixed structure,such as embolic coils and venous indwelling needles,constructing a universal hemostatic coating has great significance for improving the hemostatic performance.At present,most of the hemostatic coatings rely on physical coating.Although they have a good hemostatic effect,the stability and safety are controversial.Therefore,a universal hemostatic coating with a simple and stable structure that can be chemically combined with existing hemostatic materials has important significance.This paper will develop a new polymer hemostatic coating with a simple structure and chemically combine with hemostatic materials.Chitosan,which is a natural polycationic polysaccharide,is used as the matrix.The negatively charged carboxyl group and the positively charged quaternary ammonium group are modified to prepare quaternized carboxymethyl chitosan(QCCS)as a polymer hemostatic coating layer.Chitosan is rich in active amino groups,which is convenient for further chemical combination with existing hemostatic materials.The first part of the work is the preparation and characterization of hemostatic polymers.Carboxymethyl chitosan was prepared from chitosan with a carboxymethyl substitution degree of 73%,and then QCCS with different quaternary ammonium salt contents was synthesized from carboxymethyl chitosan,with quaternary ammonium salt contents of 7.7%(QCCS-1)?9.6%(QCCS-2)?34.6%(QCCS-3).The prepared QCCS has good blood compatibility.QCCS-1 can increase the aggregation effect of blood cells.The second part of the work was to prepare aldehyde-based porous starch(PSP-CHO)from porous starch(PSP),and then modify QCCS-1 onto PSP-CHO by Schiff base reaction as a hemostatic coating,to synthesize hemostatic powder PSP@QCCS-1.In vitro blood coagulation test of whole blood,blood cell adhesion test,platelet adhesion and activation test prove that PSP@QCCS-1 can significantly improve the whole blood coagulation speed,increase adhesion degree of blood cells and platelets.PSP@QCCS-1 significantly reduces the time required to form fibrin clots by affecting endogenous coagulation pathway,without affecting the exogenous coagulation pathway.In the experimental model of rat broken tail hemostasis,PSP@QCCS-1 significantly shortened the hemostasis time and reduced the amount of blood loss.In summary,we used chitosan as the matrix which is rich in active amino groups,and modified the negatively charged carboxyl group and positively charged quaternary ammonium group to prepare quaternized carboxymethyl chitosan.The polymer has a good effect of promoting blood coagulation.Then we used it as a polymer hemostatic coating to modify the porous starch.The current research use polymer hemostatic coating to improve the coagulation performance of existing hemostatic materials is of great significance.