Preparation And Performance Research Of Composite Hemostatic Materials Of Oxidized Cellulose/Chitosan

Good hemostasis is a very important part in trauma and surgical treatment.The application of excellent hemostatic materials can greatly reduce the incidence of surgical complications and death.Chitosan(CS)has good biocompatibility,biodegradability,and the function of promoting the repair of damaged tissue.Furthermore,it can also promote coagulation and inhibit the growth of a variety of bacteria and fungi.However,pure chitosan hemostatic materials have some disadvantages in the application,such as poor mechanical properties,high brittleness and rapid degradation.Cellulose and its derivatives are rich in reserves,cost-effective,high-intensity,non-toxic and easily degradable,which make cellulose-based materials have the potentiality in biomedical applications.Thus,Combining the respective characteristics of the two materials and com pensating the deficiency of the single element can construct a new type of functional cellulose chitosan-based hemostatic materials.In this paper,based on the preparation of two kinds of oxidized cellulose,different formulations of oxidized cellulose/chitosan composites were constructed,and their physicochemical properties and biological properties were evaluated.The results are as follows:1.Dialdehyde cellulose(DAC)was successfully prepared by sodium periodate.The optimal oxidation conditions were determined by orthogonality:the reaction temperature was 50°C,the mass ratio of sodium periodate to cellulose was 1.0,the value of pH was 4,and the reaction time was 1 h.Under the optimum reaction conditions,the content of aldehyde was up to 1.94 mmol/g.Then nano-oxidized cellulose(OCNF)was prepared in TEMPO/NaBr/NaClO system,and its structure were proved by infrared spectroscopy,particle size and other characteristics.2.Dialdehyde cellulose and chitosan were blended and cross-linked to develop different formulations of sodium periodate oxidized cellulose/chitosan composites(DAC/CS),and the physicochemical properties and biological activities were studied.The results showed that the addition of oxidized cellulose reduced the water absorption,porosity,and water vapor transmission rate of the composites to varying degrees,but it had significantly enhanced mechanical properties,improved degradation and good bacteriostatic properties.In order to meet the requirements of biomaterials and better apply to chronic wound healing,5%-DAC/CS composite materials were selected as a comprehensive consideration.The composite membranes possessed the water absorption rate of 144%,water vapor transmission rate of 1.24Kg/(24h·m~2),and tensile strength of 36.51 MPa.The degradation of the composite membranes were 23.05%in four weeks.The composite sponges had the water absorption rate of 1243%,porosity of 86.51%,water vapor transmission rate as 4.13Kg/(24h·m~2),and tensile property of 0.28 MPa.The composite membranes could be degraded 25%in four weeks.In additions,the composite materials also showed good antibacterial effect.3.Similarly,the potential of OCNF/CS composites as haemostatic materials were explored.The OCNF/CS composites expressed significantly improved mechanical properties,good water absorption,and air permeability.Also,their antibacterial effects were obvious,which can completely inhibit bacteria in the blood that is 100 times their own mass.Nanometer size of OCNF had less influence on chitosan matrix and could provide stronger mechanical strength than DAC.Therefore,compared with DAC/CS composites,ONFC/CS composites had better performance.