Preparation And Research Of Antibacterial And Hemostatic Dressing Based On Dopamine Modified GelMA

After a major trauma to the human body,problems such as bacterial infection and excessive blood loss often occur.In the early stage of wound healing,bacteria can easily enter the wound and cause serious infection,which greatly increases the probability of death.In recent years,methacrylic acid modified gelatin(GelMA)has attracted the research of many scholars due to its good biocompatibility and biodegradability.However,due to its poor adhesion,lack of antibacterial activity and insignificant hemostatic effect,GelMA is less used in the field of wound repair.Based on this,in this study,gelatin(Gelatin),methacrylic anhydride(MA)and dopamine hydrochloride(DA)were used as raw materials to react with 1-ethyl-(3-dimethylaminopropyl)(EDC)and N-hydroxysuccinimide(NHS).Then,A series of dopamine-modified GelMA(GelMA-DA)were synthesized.Followed by the preparation of silver nanoparticles/graphene oxide composites(Ag NPs/GO)and quaternized chitosan(QCS),respectively constructed GelMA-DA/Ag NPs/GO hydrogel dressing(GelMA-DA/Ag NPs/GO)and GelMA-DA/QCS/glycerol(Gly)hemostasis Sponge dressing(GelMA-DA/QCS/Gly).In this paper,Gelatin was first modified,and MA and DA were grafted onto the Gelatin to obtain GelMA-DA.The results showed that the adhesive strength of the hydrogel modified by dopamine was significantly improved,and it increased with the increase of the degree of substitution of the catechol group.The degree of substitution of phenol groups increases and the compressive modulus decreases with the increase of the degree of substitution of catechol groups.The cytocompatibility is always at a good level.In order to endow the GelMA-DA hydrogel with antibacterial activity,GelMA-DA/Ag NPs/GO hydrogel dressings were prepared by further compounding the synthesized Ag NPs/GO into the GelMA-DA hydrogel.Effects of concentration of Ag NPs/GO on swelling ratio,bond strength and compressive modulus of GelMADA/Ag NPs/GO hydrogels.Since nanomaterials usually have certain cytotoxicity,the GelMA-DA/Ag NPs/GO with the highest antibacterial activity was optimized under the condition that the GelMA-DA/Ag NPs/GO hydrogel has good cytocompatibility and hemocompatibility.The results show that the GelMA-DA/Ag NPs/GO hydrogel has better swelling properties and bonding strength when the Ag NPs/GO content is 1-2 mg/m L.While the Ag NPs/GO content is higher than 2 mg/m L,the compressive modulus of GelMA-DA/Ag NPs/GO hydrogel decreased and the microstructure collapsed.On the other hand,when the content of Ag NPs/GO is greater than 2 mg/m L,the cytocompatibility of GelMA-DA/Ag NPs/GO hydrogel is poor,but the antibacterial activity is at 2 mg/m L of Ag NPs/GO significantly increased.Therefore,the optimal content of Ag NPs/GO is 2 mg/m L.Subsequently,the hemolysis rate of GelMA-DA/Ag NPs/GO hydrogel was less than 5% when the content of Ag NPs/GO was 2 mg/m L,which also proved that the GelMA-DA/Ag NPs/GO hydrogel can The application of hydrogel dressings has potential application value.However,when the human body suffers major trauma,it is often accompanied by uncontrollable bleeding.In emergency situations,it is not only necessary to prevent bacterial infection,but also to control blood loss quickly and effectively,so GelMADA/quaternized chitosan(QCS)/glycerol(Gly)hemostatic sponge dressings(GelMADA/QCS/Gly)were constructed.The optimal composition of GelMA-DA/QCS/Gly sponge dressing with excellent water absorption performance,good coagulation performance,soft texture and easy degradation was optimized by orthogonal experiment,and the adhesion properties,cytocompatibility,hemocompatibility,antibacterial properties,in vivo coagulation properties and coagulation mechanism of GelMA-DA/QCS/Gly was further explored.The results showed that the optimal composition of GelMA-DA/QCS/Gly sponge was 5% GelMA-DA,3% QCS and 3%Gly,and the GelMA-DA/QCS/Gly sponge dressing also had good cytocompatibility,blood compatibility and antibacterial activity.The in vivo hemostatic test results showed that compared with commercial gelatin sponge and chitosan sponge,GelMADA/QCS/Gly sponge could more rapidly reduce the amount of bleeding in the tail vein and liver hemorrhage model of SD mice,and shorten the blood loss time.Coagulation mechanism shows that GelMA-DA/QCS/Gly sponge dressings can adsorb red blood cells,promote endogenous hemostasis and coagulation,and reduce blood loss in the early stage of trauma.