Preparation Of Antibacterial And Anti-inflammatory ZIF-8@Rutin Nanocomposite Scaffolds For Accelerate Infected Wound Healing

Objective:Rutin was loaded into the ZIF-8 to make a new type of nanoparticle complex ZIF-8@Rutin.ZIF-8@Rutin was tested for partial physiochemical properties and evaluated for antibacterial,anti-inflammatory and promoting wound healing,both in vitro and in vivo.Methods:ZIF-8 was prepared by solvent thermal synthesis,ZIF-8 and Rutin were synthesized from ZIF-8@Rutin in a 1:1 ratio using the principle of electrostatic adsorption,and the synthesized ZIF-8 and ZIF-8@Rutin were analyzed for SEM,TEM,XRD and HPLC,respectively.ZIF-8,Rutin,and ZIF-8@Rutin at 0μg ml^-1,30μg ml^-1,40μg ml^-1,50μg ml^-1and 60μg ml^-1were prepared.ZIF-8 and ZIF-8@Rutin were selected using CCK-8and cell dead staining,and this concentration was used for subsequent experiments.The antimicrobial properties of ZIF-8,Rutin,and ZIF-8@Rutin.Polymerase chain reaction（PCR）using RAW 264.7 to test the M1 pro-inflammatory molecules and M2anti-inflammatory molecules to assess the anti-inflammatory properties of ZIF-8,Rutin and ZIF-8@Rutin.In the in vivo anti-inflammatory experiment,BALB/c mice were used to record the healing area of the back wound of different mice at 0,2,4,6,8 and 10days of the inflammatory model,meanwhile,the tissues around the back wound of all mice were removed.H&E staining and Masson staining results will demonstrate the histological characteristics of wound healing in different treatment groups,and wound regeneration was evaluated by observing the re-epithelialization of tissues,infiltration of inflammatory cells,and deposition of collagen fibers.Meanwhile,the mechanism by which ZIF-8@Rutin played an anti-inflammatory role we quantified the expression of inflammation-related cytokines in skin tissue by immunohistochemical staining and immunofluorescence staining.We selected TNF-αas a typical pro-inflammatory factor and selected Arg-1 as a typical anti-inflammatory factor to determine the anti-inflammatory ability of the nanocomposites in vivo.Statistical analysis of the data was performed using the Graph Pad Prism 8.0.2 software package.Results:A series of characterization results showed that the loading of Rutin did not alter the original structure of ZIF-8,on the contrary,the synthetic ZIF-8@Rutin had lower cytotoxicity than ZIF-8 at concentrations lower than 40μg ml^-1.The continuous release of Zn²⁺and Rutin gave ZIF-8@Rutin good antibacterial properties,superoxide dismutase and catalase activity of the composite nanoparticles.The incorporation of Rutin slightly reduced the antimicrobial activity,including the ability to kill E.coli and Staphylococcus aureus,but was still statistically different.In in vitro tests,ZIF-8@Rutin increased the polarization of macrophage M2 type,promoted the gene expression of related anti-inflammatory factors（IL-10,Arg-1,TGF-α）,and reshaped inflammatory immunity,thus showing good therapeutic effects on wound healing of bacterial infection in animal models.Conclusion:ZIF-8@Rutin with"flower-like"morphology can be synthesized by the principle of electrostatic adsorption.The synthetic new composite nanoparticles have antibacterial,anti-inflammatory and wound healing properties,which provides a new idea for further treatment of infected wounds.