Study On The Design And Application Of Multieffct Antibacterial Dressing

Skin is the first barrier against environmental damage.Once this barrier is broken,the wound-healing process is triggered at the site of the wound to repair the integrity of the skin and restore its normal function.Wound healing is a coordinated and dynamic interaction consisting mainly of four overlapping but distinct stages of hemostasis,inflammation,proliferation and remodeling.Advanced medical dressings need to meet the requirements of air permeability,hygroscopic balance,antibacterial activity and mechanical strength.However,the balance between air permeability and hygroscopicity depends largely on the porous structure,which may lead to a decrease in mechanical properties and antimicrobial activity of dressings.In addition,most of these medical dressings can only repair a single type of wound,which limits their wide clinical application.Therefore,the development of antibacterial dressings with excellent mechanical properties and functions in different wound healing processes is still a main research direction in the future.Based on the above analysis,a series of multi-effect antibacterial dressings were prepared in this paper,which are used to stop bleeding,fight bacteria,regulate inflammatory response,promote cell proliferation and wound healing.The performance,safety and application of these material systems were explored to provide new ideas for effective treatment of bacterial infection and significant promotion of wound healing.It mainly includes the following three parts:(1)Using electrostatic spinning technology to prepare nanofibrous membrane with three-dimensional network structure(MAP nanofibrous membrane),as a dressing to promote wound healing,it can maintain the hygroscopic balance at the wound,release antibiotics as needed,and inactivate bacteria with heat therapy to fight bacterial infection and promote wound healing.Two-dimensional(2D)MXene nanosheets with sharp edges can destroy bacterial membranes and enhance the thermal sensitivity of bacteria.On the other hand,the release of amoxicillin(AMX)can be promoted under the condition of near infrared light irradiation.At the same time,NIR irradiation can activate the photothermal activity of MXene,and the resulting local hyperthermia can destroy the integrity of bacterial cell membrane,leading to bacterial inactivation in a synergistic antibacterial way.(2)A multi-effect antibacterial hydrogel dressing(QMPD hydrogel)that can combine photothermal effect was constructed by UV-induced double bond polymerization.It has the function of adhesion,hemostasis,antibacterial,antiinflammatory and promoting wound healing.Hydrogels contain a broad spectrum and low toxic quaternary ammonium chitosan(QCS,positively charged)that provide high efficiency and long-lasting antibacterial properties.In addition,polyvinylpyrrolidone(PVP)was added to enhance the stability and mechanical properties of the hydrogel system.More importantly,the hydrogel can be completely degraded and absorbed within11 days to prevent secondary injury to the wound.QMPD hydrogel has outstanding wet tissue adhesion due to hydrogen bond and dopamine(DA)adhesion.In addition,the oxidation process of DA can consume free radicals and play an antioxidant role.Under near-infrared irradiation,the oxidative product polydopamine(PDA)can cause local hyperthermia,kill bacteria in the wound surface and reduce the occurrence of inflammation.These functions demonstrate the great potential of QMPD hydrogel in antibacterial and wound healing.(3)An antibacterial hydrogel dressing(QMSF hydrogel)promoting angiogenesis and inflammatory factor transformation was synthesized by one-step method.On the basis of the study in the previous chapter,the hydrogel formed by QCS-MA and PVP with adhesive,hemostatic and antibacterial effects was used as the carrier,and compound Surfactin(SF)was introduced by hydrogen bonding.Due to the presence of QCS and SF,QMSF hydrogels not only improved the antibacterial effect and mechanical properties of hydrogels,but also promoted angiogenesis,inflammatory factor conversion and hemostasis.The hydrogel is an adhesive hydrogel with strong shape adaptability,which can fill deep wound surface,promote the contact between hydrogel and wet wound surface.It also provided sufficient microenvironment for cell proliferation,angiogenesis,granulation tissue formation and reepithelialization,which significantly accelerated the process of wound healing.More importantly,QMSF hydrogel accelerates the healing of bacteria-infected skin wounds by promoting angiogenesis,collagen deposition,inflammatory factor transformation,and granulation tissue formation.Therefore,QMSF hydrogel is expected to provide a new method to promote angiogenesis,inflammatory factor conversion and accelerate the healing of chronic skin wounds.