Study On Burns Healing And Hemostatic Properties Of Chitosan/Tilapia Peptides Biomedical Materials

Trauma is one of the most common diseases in human tissues or organs.Local wars,terrorist attacks,natural disasters and accidents such as cuts,falls,fall injuries,car accidents and burns are all important causes of trauma.The treatment of trauma patients requires not only timely hemostasis,but also the effective recovery of tissue regeneration and function.Due to the high risk of permanent scarring in this type of disease,patients often have a heavy medical burden and psychological stress,which threatens human health.Therefore,effectively control post-traumatic hemorrhage,achieve rapid repair of tissues and effective recovery of functions are hotspot and difficult point in the research and development of wound-repair biomedical materials.Both chitosan(CS)and tilapia peptides(TP)have good biocompatibility,biodegradability,non-toxicity,no immunogenicity,and a variety of biological activities,and have great potential to be developed into hemostatic and wound repair medical materials.This study uses CS and TP as raw materials,through biological activity screening,ratio optimization,material formation and mechanism analysis,not only lays the foundation for the preparation of wound-repair biomedical materials based on chitosan/tilapia peptide,but also provides a methodology for the high value utilization of marine living resources.The main research contents and results are as follows:1.The antibacterial activity of chitosan with different molecular weight at different concentrations to Staphylococcus aureus and Escherichia coli was studied.The results showed that inhibition zone diameter increased with the increase of CS concentration,and CS with the molecular weight of 100 kDa had the best antibacterial effect against S.aureus;CS with a molecular weight of 3.5 kDa or 100 kDa has significant antibacterial activity against E.coil,indicating that CS with a molecular weight of 3.5 kDa and 100 kDa can meet the needs of skin wound repair and hemostasis.The biocompatibility of CS and TP was evaluated by culturing mouse fibroblasts(L929).The results showed that CS and TP had no obvious cytotoxicity,and had good biocompatibility and inhibition of apoptosis.By observing the effect ofCS and TP composite hydrogel on the healing process of skin burns on the back of new zealand rabbits,it was found that the hydrogel has a good antibacterial activity and synergistic effect on promoting burn healing.2.The injury repair of CS and TP complexes was observed by establishing a damage model of human umbilical vein endothelial cells(HUVEC)injured by AG490.The results showed that after exposure to AG490,the viability of HUVEC cells decreased,and the expression of STAT3 and VEGF decreased.After pretreatment with CS and TP(3:7),cell damage was reduced,proliferative activity was increased,and apoptosis rate was decreased.Mechanism studies have found that this complex up-regulates STAT3 and VEGF expression via the JAK2/STAT3 signaling pathway.3.The effects of different proportions of CS on the secondary structure of TP were studied by Fourier transform infrared spectroscopy(FTIR)and circular dichroism(CD).It is found that when the mass ratio of CS to TP is 3:7,the antiparallel of the secondary structure of TP is firstly accumulated into an ?-helix,and then arranged into a ?-corner structure.The CS/TP hydrogel prepared in this composite ratio can can significantly accelerate the rate of wound healing,promote the synthesis of total protein and hydroxyproline in granulation tissue,reduce the local inflammatory reaction of wounds,and accelerate the formation and epithelialization of new blood vessels.The results of Masson staining showed that the density of collagen fibers in the wound tissue of New Zealand rabbit skin in the hydrogel treatment group was uniform and arranged,and the collagen content was significantly higher than other groups.Immunohistochemistry results showed that the composite hydrogel significantly up-regulated the expression of STAT3 and VEGF in the above wound tissue.4.The chitosan/tilapia peptide microspheres(CS/TPM)were prepared by ion crosslinking method.The results showed that the encapsulation efficiency and drug loading of TP in the microspheres were 64.7 % and 10.6 %,respectively.It has a uniform spherical shape with a smooth surface and an average particle size of 15 ?m.The storage stability of TP in microspheres is obviously improved,and has a good sustained release effect.5.The CS/TPM was used as a filler to construct a chitosan/tilapia polypeptide composite sponge(S-CS/TPM),which has good water absorption and safety(no cytotoxicity).The results of in vitro hemostasis evaluation showed that S-CS/TPM can accelerate blood coagulation,have low hemolytic activity and promote red bloodcell adsorption and platelet adhesion.At the same time,S-CS/TPM can promote the conversion of fibrinogen to fibrin in the blood.The evaluation results of new Zealand rabbit ear artery and femoral artery hemostasis show that S-CS/TPM has faster hemostasis time and less bleeding than CS sponge and CS/TPM.Both in vivo and in vitro studies have shown that S-CS/TPM is a promising hemostatic material.