In-situ Sulfuration Of Cu-based Metal-organic Framework For Rapid Bacteria-killing Under Near-infrared Light

Facing the challenge of increasing severe health problems caused by the bacterial drug resistance,it is in great need for us to develop new antibacterial strategies.Recently,with the rapid development of photo-responsive materials,photodynamic anti-bacterial(PDA)therapy and photothermal anti-bacterial(PTA)have emerged as new therapeutic strategies instead of conventional antibiotics treatment.In this experiment,HKUST-1,a Cu-based metal-organic framework(MOF)was used to fabricate CuS NPs incorporated MOF via a simple in-situ sulfuration process,which exhibited excellent photo-responsive property.Based upon the cooperative effect of PDA,PTA and copper ion release,the composites exhibited excellent and quick antibacterial effect.During the experiment,by controlling the sulfuration time,the different amounts of CuS NPs were embedded in HKUST-1.SEM observation and phase analysis revealed that small amount of Cu²⁺ions from HKUST-1 were converted into CuS NPs.It is found that with the increase of CuS NPs in the MOF structure,the near-infrared light absorption and the photothermal conversion ability of the composite increased significantly,while the photodynamic ability is more dependent on the integrity of the MOF structure.Through the antibacterial test,the samples with suitable sulfuration time exhibited an effective disinfection efficacy of 99.70%and 99.80%against Staphylococcus aureus and Escherichia coli within 20 min irradiation of near-infrared(NIR)light,respectively.Cytotoxicity experiment found that the materials had little inhibition on the normal growth of cells with a prolonged contact,which may be caused by the release of a small amount of copper ions.In addition,in order to improve the poor dispersion of HKUST-1 in aqueous solution,the polydopamine shell was successfully wrapped on the surface of the sulfurized Cu-based MOF through the oxidative polymerization of dopamine in alkaline environment.Besides improving the dispersion,the NIR light absorption and light response performances of the material were enhanced due to the light absorption nature of polydopamine itself.As a result,antibacterial efficiency increased.