Preparation And Characterization Of Hemostatic Sponges And Wound Dressings Based On Chitosan

Skin trauma is a common health problem that has plagued humans since ancient times.If the skin wound does not heal for a long time,it will cause bacterial infection,resulting in wound ulceration and even sepsis and other serious consequences.Wound healing generally goes through four stages,including hemostasis,inflammation,proliferation and healing,and hemostasis is the first key step.Traditional hemostatic materials and wound dressing are not ideal for skin wound repair,and there are some limitations.Therefore,it is necessary to develop new natural and green bio-medical materials with biocompatibility,antibleeding,antibacterial,bioadhesion and biodegradability for hemostasis and wound healing.Chitosan is a kind of natural renewable biomaterial,with excellent biocompatibility,biodegradability and coagulation ability,which is widely used in the field of biomedicine.In this paper,chitosan derivatives and chitosan were used as substrates to prepare functional composite hemostatic sponge samples and functional composite hydrogel wound dressings,and their physical and chemical properties were studied and verified by animal models.Specific research results are as follows:(1)Through freezing and vacuum drying,carboxymethyl chitosan/sodium alginate composite sponges with different proportions were successfully prepared for wound hemostasis.The composite sponges showed loose porous structure,and the water absorption and porosity of the composite sponges could reach 14.5 g/g and 75%,respectively.The toughness and compression modulus of the composite sponge samples were 0.54 MPa and 0.045 J/m~3.In vitro degradation experiments showed that the degradation rate of the composite sponge samples with different proportions reached more than 50%,and the cytotoxicity test results showed that the cell activity of the composite sponge samples were more than 80%,and the composite sponge samples had no obvious cytotoxicity.In addition,the composite sponge samples also have good antibacterial activity.The hemostatic performance of the composite sponge CS-12 was verified by the mouse model of tail amputation hemorrhage.Compared with the untreated control group,the hemostatic time and blood loss of the composite sponge CS-12 were reduced to 94.3 s and 36 mg,so the hemostatic time and blood stop volume were reduced by 69.5%and 66.8%,respectively,showing a good hemostatic effect.Obviously,composite sponge samples have good water absorption,antibacterial and biocompatibility,can achieve ideal hemostatic effect,and is expected to be used as hemostatic materials.(2)Potassium hydroxide/lithium hydroxide/urea water system was used as the solvent of chitosan and sodium alginate.After several freezing and thawing processes,uniform blends were successfully prepared.Using epichlorohydrin,calcium chloride and tannic acid as crosslinking agents,chitosan/sodium alginate composite hydrogels with different mass ratios were successfully prepared.The composite hydrogel CSA-31 has a high porosity of 77.3%,in vitro degradation rate of 60%,compression modulus of 0.073 MPa and toughness of 0.23 J/m~3.It also has a certain p H response and antibacterial activity.The results of cytotoxicity test confirmed that the composite hydrogels had good biocompatibility.Finally,its ability to promote wound healing was verified by mouse wound healing model.Compared with untreated control group,composite hydrogel CS-31 had the best effect in promoting wound healing,which is expected to be applied in clinical medical field as an antibacterial wound dressing.In summary,this study successfully prepared chitosan derivatives antibacterial functional composite hemostatic material and chitosan antibacterial functional composite wound dressing,and studied their structures and characterized their properties.The structures showed that both composite materials had potential application value and were expected to be used in the biomedical industry.