Preparation And Application Of Alginate-based Gel Sponge Wound Dressing

As a polymer material with excellent biocompatibility,alginate polymer has been applied to the design and development of various wound dressings.Its main role is to improve the hydrophilicity of wound dressings,create a moist environment,and accelerate wound recovery.However,alginate dressings have the defects of poor hemostasis performance and no antibacterial activity.In order to make alginate dressing have excellent hemostatic performance,one method is to prepare it into a hydrogel adhesive,which can block the damaged blood vessels by bonding the wound tissue to achieve the purpose of hemostasis.However,this method has the defects of high toxicity and difficult removal of residual crosslinking agent.Another common method is to prepare alginate particles.They can stop bleeding by instantaneous high fluid absorption and platelet adhesion,but they may enter the blood circulation system through the wound and induce biological safety problems such as vascular embolism.Therefore,it is of great significance to develop a rapid hemostatic and healing alginate-based medical dressing without cross-linking agent toxicity,easy removal and no biosafety problems.To solve the above problems,this paper conducts the following two parts of research.(1)In order to endow the dressing with excellent hemostatic properties,chitosan oligosaccharide chemically modified graphene oxide(CG)was introduced into the natural polymer alginate network,and a gel sponge dressing with rapid hemostasis,antibacterial and healing was successfully prepared.The dressing achieved rapid hemostasis by rapidly absorbing the dual hemostatic mechanism of the strong stimulation of blood cells enriched by blood and graphene oxide on platelets.Studies have shown that the hemostasis performance of the dressing increases with the increase of CG content,and the fastest hemostasis can be achieved within 10 s.At the same time,the CG-loaded wound dressing can significantly accelerate wound healing by accelerating granulation tissue growth and promoting vascular remodeling.The full-thickness wound healing experiment showed that the wound covered with this dressing could be almost completely healed within 12 days(92.11%),far exceeding the blank control and the dressing without CG loading.(2)In order to maintain the good hemostasis performance of the dressing and strengthen the antibacterial and biocompatibility of the dressing on this basis,the dopamine coated reduced graphene oxide(r GO-PDA)was prepared by using the excellent biocompatibility and mild reduction performance of dopamine.The r GO-PDA was introduced into the calcium alginate substrate,and the dressing was successfully endowed with better antibacterial property(significant indigenous effect on Gram-negative and positive bacteria),biocompatibility(cell proliferation rate was more than 85% of the unloaded dressing)and water retention property(water content was more than 60% within48 h).Full-thickness wound healing experiments showed that a large number of collagen deposition and neovascularization were observed,and close to complete healing within 12days(95.18%).In addition,reduced graphene oxide can still strongly stimulate platelets to activate and activate coagulation cascade.Hemostatic experiments show that it can completely stop bleeding within 30 s.This kind of small molecule functionalized graphene oxide is loaded on alginate substrate to obtain wound dressings with multiple functions such as hemostasis,antibacterial and healing promotion,which provides a simple,practical and effective method for the subsequent development of dressings.