| Backgrounds: In recent years,both tropical rainforest operations in the Southern Theater of Operations and future operations in special environments require line of fire emergency equipment with special environmental combat functions that can be used in high humidity environments.Because high humidity environments can easily cause intracellular dehydration and interstitial edema at the wound site,directly affecting the healing and tissue repair process of war wounds;At the same time,local swelling can also lead to blood transportation,insufficient arterial blood supply,and even tissue necrosis.The difficulties in hemostasis of wounds in high humidity environment are as follows:(1)Due to the interfacial water layer between wounds and hemostatic materials,hemostatic materials cannot play the hemostatic function;(2)In high humidity environment,wound tissue and hemostatic material can not be efficiently bonded,so it is easy to detach.At present,the first aid wound dressing,first aid hemostatic bandage,self-adhesive elastic bandage and other equipment developed in our country can not meet the needs of troops in high humidity environment.Therefore,it is urgent to develop a kind of material that can be used in high humidity environment and has high efficiency hemostatic function.Objective: It was found that mussel foot protein contains a large number of 3,4-dihydroxy-L-phenylalanine(DOPA),lysine and histidine,and these amino acids are rich in side chains of catechol,primary amine and secondary amine,which enables mussels to remove the "interfacial water layer" and adhere to various basement surfaces with high wet adhesion ability.Inspired by this,the mussel bionics technology is expected to explore the development of hemostatic materials for use in high humidity environment.Based on this,this project intends to use common organic hemostatic materials such as chitosan and collagen as the base material,introduce catechol groups into hemostatic materials and realize organic combination through modification,polymer polymerization,crosslinking and other means,explore and study the adhesive sealing hemostatic ability of wounds in high humidity environment,and lay a foundation for the research and development of key technologies for rapid hemostatic in combat sites in special environment.Method:(1)Hydrogel hemostatic material was formed by cross-linking chitosan with the self-polymerization of dopamine through the Michael addition reaction.The functional groups,adhesion properties and hemostatic effect of polydopamine/chitosan hemostatic materials were evaluated by infrared spectroscopy,bond shear strength and in vitro coagulation.(2)In order to introduce more catechol groups into the hemostatic material and give full play to the wet adhesion ability of catechol groups,3,4-dimethoxy-styrene and 4-vinylbenzoic acid were used to initiate polymerization through potassium persulfate.The copolymer of catechol(3,4-dihydroxystyrene-copolymer-4-vinylbenzoic acid)[P(DHS-co-VBA)] was prepared by methoxy-deprotection.The molecular weight,structure and physicochemical properties of DHS-co-VBA copolymer P(DHS-co-VBA)were analyzed and evaluated by gel permeation chromatography(GPC),nuclear magnetic resonance hydrogen spectroscopy(NMR)and Fourier transform infrared spectroscopy(FTIR).(3)Microfiber collagen was blended with prepared catechol copolymer P(DHS-co-VBA),part of the solvent was evaporated,and P(DHS-co-VBA)/ microfiber collagen hydrogel hemostatic material was prepared.The hydrophilic and hydrophobic properties,wet adhesion and cytotoxicity of P(DHS-co-VBA)/ microfiber collagen hydrogels were evaluated.The hemostatic effect of P(DHS-co-VBA)/ microfiber collagen hydrogel on wet surface tissue was evaluated by in vitro coagulation experiment and hemostasis in mouse liver tissue.Results:(1)The infrared spectrum test results show that polydopamine and chitosan have successfully crosslinked.The adhesion strength test results show that chitosan: when dopamine is 3:1,the adhesion strength of polydopamine/chitosan hydrogel hemostatic material is the highest,but the adhesion strength on dry glass surface is lower than that of common glue sold on the market.And wet pig skin surface test results did not show better wet adhesion effect;CBT and TEG results showed that polydopamine/chitosan showed better in vitro coagulation effect than chitosan alone.(2)The copolymer P(DHS-co-VBA)was prepared by free radical polymerization.The results of gel permeation chromatography showed that the molecular weight and dispersion coefficient of the copolymer P(DHS-co-VBA)were in line with expectations.The results of NMR and Fourier infrared spectroscopy show that the copolymer P(DHS-co-VBA)of catechol has been prepared successfully.(3)P(DHS-co-VBA)/microfiber collagen hydrogel hemostatic material,with good hydrophilicity;At the same time,it has strong wet adhesion properties,stronger than many commercially available adhesives.Hydrogel hemostatic material has low cytotoxicity and good biocompatibility.The results of in vitro coagulation and animal hemostatic experiments also showed that hydrogel hemostatic material has good hemostatic performance.Conclusion:(1)Due to the preparation process of polydopamine/chitosan hydrogel hemostatic material,a large number of catechol groups are consumed,resulting in the hemostatic material does not show good adhesion ability on wet and dry surfaces.However,the introduction of catechol groups can improve the hemostatic effect of chitosan.(2)P(DHS-co-VBA)/ microfiber collagen hemostatic material prepared by polymerization reaction.Due to the introduction of a large number of catechol groups after demethoxylation of reaction monomer 3,4-dimethoxy-styrene,the hydrogel material has good wet adhesion ability and hemostatic effect.The mussel bionic technology is a good polymer hemostatic material for quick hemostasis,high adhesion and safety.It shows that mussel bionic technology has great application potential in the rapid hemostasis of war wounds in high humidity environment. |
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