Synthesis Of TiO₂@MIL-101（Fe）@Ag For Antibactrial Application

Nowdays,bacterial infection has become a major global concern.It affects the health of tens of millions of people every year and causes serious harm to both medical health and socio-economic development.With the abuse of traditional antibiotics,bacteria have developed drug resistance,so the development of high-efficiency antibacterial materials with little bacterial resistance has become an urgent problem to be solved in the field of antibacteria.However,traditional antibacterial materials have their own advantages,disadvantages and limitations.Composite antibacterial materials can enhance antibacterial properties and broaden the application scope of antibacterial materials,which has become the most promising strategy at present.In this paper,we will use hollow Ti O₂ microspheres and P25 as carriers to composite MIL-101（Fe）,and then load silver nanoparticles on the surface to prepare two kinds of Ti O₂@MIL-101（Fe）@Ag nanocomposites with different sizes.It is then applied to the study of sterilization and elimination of bacterial biofilms.The main research contents and results are as follows:（1）We first prepared hollow Ti O₂ microspheres（HP-Ti O₂）by biomimetic synthesis and sol-gel method using S.aureus as a biological template.It was then combined with MIL-101（Fe）.Finally,the silver nanoparticles（Ag NPs）were loaded on the surface of the material by tannic acid（TA）reduction,and the material HP-Ti O₂@MIL-101（Fe）@Ag composite was obtained.The materials were systematically characterized and analyzed by means of SEM,TEM,EDS,ICP-MS.Through TMB oxidation experiments,it was found that the composite material has excellent peroxidase activity in neutral and slightly acidic environments.（2）The bactericidal properties of HP-Ti O₂@MIL-101（Fe）@Ag composites were analyzed.The results showed that 95%of E.coli could be killed when the material concentration was 2μg/m L;93%of S.aureus could be killed when the material concentration was 32μg/m L.Moreover,the effective bactericidal performance of the material on E.coli and S.aureus was increased by 8 times and 16 times after adding H₂O₂.It is shown that the HP-Ti O₂@MIL-101（Fe）@Ag composite is an excellent antibacterial material.At the same time,the ability of the material to remove the bacterial biofilm of S.aureus was also studied.The results showed that the material of512μg/m L after adding 1 mmol/L H₂O₂ could remove 50%of the bacterial biofilm,which was not ideal for removing bacterial biofilm.（3）We using commercial titanium dioxide P25 as a carrier,first composited MIL-101（Fe）on its surface,and then used TA to in situ reduce and grow silver nanoparticles Ag NPs on the surface of the material to obtain P25@MIL-101（Fe）@Ag composites.In addition,we systematically characterized and analyzed the morphology,structure,surface composition and element distribution of the material by means of SEM,TEM,EDS elemental characterization,ICP-MS and other means.And through TMB oxidation experiments,it is found that the P25@MIL-101（Fe）@Ag composite has excellent peroxidase activity under neutral and slightly acidic conditions.（4）The bactericidal properties of the P25@MIL-101（Fe）@Ag composite were analyzed.When the concentration of the material was 2μg/m L,it could kill 98%of E.coli.When the material concentration is 32μg/m L,it can kill 99%of S.aureus.Interestingly,when 1 mmol/L H₂O₂ was added,the effective antibacterial performance of the material against E.coli was increased by 16 times,and the effective antibacterial performance against S.aureus was increased by 64 times.This is a 2.5-fold and 2.6-fold improvement over HP-Ti O₂@MIL-101（Fe）@Ag.Finally,the S.aureus bacterial biofilm ability experiment showed that in the presence of H₂O₂,the material concentration of 128μg/m L could remove nearly 30%of the biofilm,and when the material concentration is refreshed to 512μg/m L,nearly 60%of the bacterial biofilm could be removed.Moreover,when the P25@MIL-101（Fe）@Ag composite was used as a drug-loading platform to load RFXM,the material at 32μg/m L could remove nearly 90%of bacterial biofilms.The above experiments show that P25@MIL-101（Fe）@Ag is an excellent antibacterial material with good prospect for biomedical applications.