Construction Of Functionalized Metal-Organic Framework Coating On The Surface Of Titanium

With the improvement of medical technology,biological materials are widely used in human’s disease treatment and medical rehabilitation.Due to its excellent corrosion resistance,abrasion resistance and good biocompatibility,medical titanium materials are commonly used in orthodontic treatment.However,one of the major factors leading to the failure of implant surgery is the bacterial infection of biomaterials.The commonly used treatment for bacterial infection is the use of antibiotics intravenously,but the abuse of antibiotics leads to the emergence of a large number of drug-resistant bacteria,and systemic drugs damage the body’s immune system.Therefore,a large number of new and recurrent pathogens have caused widespread disease and death.Although the implant was sterilized,it still caused serious complications due to bacterial infection in the implant site,and even resulted in death of the patient.At the same time,due to the contact between bacteria and biological medical devices,surgical implants will be infected and bacteria will be deposited and adhered in the biological medical device surface,and begins to gather rapid growth in the biological material surface,after then they start to form the serious bacterial biofilm.Biofilm not only destroy the medicinal properties of biological materials,but also lead to the surrounding tissue lesions in the implants.Based on the problems above,this study focuses on the biological material in antibacterial applications,and chooses metal-organic skeleton coordination polymerization as the research system.We select the iron metal organic skeleton containing carboxylic acid as the functional carrier,which can load the antimicrobial agents to form the metal-organic framework slow released system.At the same time,slow released iron ions have antibacterial effect,which can contribute to the cell proliferation.The bimetallic metal-organic framework with the photothermal enhancement effect has the antibacterial effect with the dual functional physical/light therapy,and has a certain repairing effect on wound healing.Based on the titanium alloy surface,the antibacterial coating was formed,and the mechanical properties of titanium substrate were fully utilized.And combined with functional metal-organic framework coating at the same time,the system has good biological activity,which promote the cells of tissues and organs repaired,finally realizes the successful application of implant biomaterials.The basic contents of the study include the following work:1.Biocompatible metal-organic framework as a novelbioplatformwith sustained antibacterial efficacy.The iron-carboxylate metal-organic framework(MOF-53 NPs)with octahedral structure was prepared by hydrothermal synthesis.Antibacterial drug molecules vancomycin(Van)as guest molecule was loaded into the MOF-53 NPs,thus forming load drug metal-organic framework composite particles(MOF-53@Van).In the PBS solution with different pH conditions(pH=5.5,6.5,7.4),long-term metal ferric ion and Van were successively detected.At the same time,the content of ferric ion was detected after the total degradation of MOF-53,which showed that the released content of metal ferric ion was extremely low,indicating the stability of MOF-53 particles.The antimicrobial effect was observed by agar plating method and bacterial morphology observation.The biocompatibility of samples was detected by MTT and cell fluorescence.2.Bimetallic organic skeleton sustained release system with dual functional antibacterial therapy for wound healing with photothermal enhancement effect.The cubic nanoparticles Prussian blue(PB NCs)were synthesized using the synthesis method of preparation of ferrous ion precipitation aging replication,and doped with different content of zinc ions,formingthe double metal containing iron and zinc ions organic skeleton nanoparticles(ZnPB NCs).By measuring the photothermal curve and the photothermal image,the photothermal properties of the Prussian blue nanoparticles could be enhanced by the doped metal zinc ions.At the same time,long-term iron ion and zinc ion sustained from PB and ZnPB NCs were tested.In vitro bacterial antibacterial tests showed that PB and ZnPB NCs had short-term photothermal antibacterial effect and the long-term physical antibacterial effect.By cytotoxicity assay of fibroblasts,the Prussian blue doped zinc ion had good biocompatibility.In vitroquantitative real-time reverse transcription chain reaction(qRT-PCR)was used to detect zinc ions could promote wound healing.Through the animal wound model in vitro,it was shown that the photothermal and metal ions have positive therapeutic effect on the wound healing of bacterial infection.3.Metal-organic framework antibacterial composite coating with visible light response was constructed based on the titanium substrate.Firstly,the surface of titanium base was polished and the ultrasonic cleaning was performed.And then,the graphene oxide was formed on the surface of titanium metal to form the titanium oxide coating(Ti/GO)by calcining.Then,carboxylic acid metal organic skeleton iron(MIL-100(Fe))was synthesized through hydrothermal synthesis method,and MIL-100(Fe)was cladded with chitosan(CS)solution to form CS@ MIL-100 particles.After that by the spin coating method,CS@MIL-100 particle was spined on the graphene oxide coating based on titanium substrate,which forming the metal organic skeleton composite coating(Ti/GO/CS@MIL-100).The antimicrobial properties and biocompatibility of metal organic matrix films were investigated.The antimicrobial properties and biocompatibility of metal organic matrix films were also investigated.