The Biomimetic Nanoparticles Loaded With Fucoidan For The Treatment Of Wound Infection Caused By Methicillin-Resistant Staphylococcus Aureus

Objective:1.Explore the ability and mechanism of Fucoidan to kill MRSA in vitro;2.Prepare the biomimetic nanoparticles with neutrophil membrane(NM)as the outer membrane,poly(lactic-co-glycolic acid)(PLGA)as the carrier and Fucoidan as the core(Fu@PLGA-NM)and test their physicochemical properties,biological properties,infection site targeting and efficacy on wound infection caused by methicillin-resistant staphylococcus aureus(MRSA).Methods:1.Detect the ability of Fucoidan to kill MRSA by bacterial coating method.The mechanism of Fucoidan to kill MRSA was elucidated by the amount of bacterial protein leakage,membrane permeability and bacterial morphology under scanning electron microscope(SEM)and transmission electron microscope(TEM).2.After extracting mouse bone marrow neutrophils and separating the cell membrane,Fu@PLGA-NM nanoparticles were prepared by phacoemulsification,and their physicochemical properties were detected by particle size,Zeta potential,TEM,encapsulation efficiency and drug loading rate.3.The cytotoxicity of Fu@PLGA-NM nanoparticles were determined by the cell counting kit(CCK-8),the biosafety of Fu@PLGA-NM nanoparticles were evaluated by main organ slices and blood biochemistry of mice.The ability to escape phagocytosis by macrophages of the fluorescent-loaded Fu@PLGA-NM nanoparticles was verified by fluorescence confocal microscopy.4.The in vivo targeting of Fu@PLGA-NM nanoparticles to the infection site were detected in vivo fluorescence technology.5.The efficacy of Fu@PLGA-NM nanoparticles on wound infection caused by MRSA were demonstrated by observing the wound healing,white blood cell count,percentage of neutrophils and tissue sections at the modeling site in mice.Results:1.Fucoidan kills MRSA by destroying the cell membrane structure.2.Fu@PLGA-NM nanoparticles are uniformly distributed and stable in aqueous solution,with an average particle size of about 250 nm,a Zeta potential of about-8.5 m V,an encapsulation rate of 8%,and a drug loading rate of 4.7%.3.The CCK-8 experiment showed that Fu@PLGA-NM nanoparticles had no obvious cytotoxicity;no abnormalities were found in the main organ sections of mice,suggesting that Fu@PLGA-NM nanoparticles had good biological safety.Moreover,Fu@PLGA-NM nanoparticles can effectively escape the phagocytosis of macrophages.4.The in vivo fluorescence results of mice suggest that compared with Fu@PLGA nanoparticles,Fu@PLGA-NM nanoparticles have significant infection site targeting.5.The wound healing status,white blood cell count,percentage of neutrophils,and tissue sections at the modeling sites in mice proved that Fu@PLGA-NM nanoparticles have a significant curative effect on wound infection caused by MRSA.Conclusion: Fucoidan effectively kills MRSA by disrupting bacterial cell membranes.Fu@PLGA-NM nano-drug delivery system has good physicochemical properties,biosafety,and infection site targeting,and has a significant therapeutic effect on wound infection caused by MRSA in mice.It has the potential to be an effective drug for the treatment of wound infection caused by MRSA.