Studies On Biodegradable Polymer Composite Coatings By Electron Beam Deposition And Their Antibacterial Properties

Bacterial infection is a serious problem associated with the clinical use of biomaterials,it is of great significance to prepare functional antimicrobial films on the surface of medical devices.In this paper,Ag/PLA composite films,ciprofloxacin/PLA composite films and ciprofloxacin/PVC composite films were deposited on single crystal silicon wafer,quartz glass,titanium wafer,aluminized polyester film and copper mesh by low power electron beam evaporation(EBD).The composition,structure and properties of these films were studied,and their antimicrobial properties were further investigated.The specific work is as follows:1)Ag/PLA composite films were prepared by EBD method using silver nitrate and polylactic acid(PLA)powder as target materials.Silver nanoparticles(AgNPs)are widely distributed in the matrix film with an average particle size of about 20 nm.The Ag element in the composite film mainly exists in the form of Ag,which is slightly agglomerated after two days,but still exists in the form of AgNPS.Composite films have better antimicrobial properties,and the antimicrobial properties of composite films deposited on silicon substrates are better than those of Staphylococcus aureus.2)Ciprofloxacin/PLA composite films were prepared by EBD method using mechanical mixtures of ciprofloxacin and PLA powder as targets.The characteristic functional groups of ciprofloxacin still exist in the composite films,so they have excellent antimicrobial properties.Among them,the composite films deposited on titanium substrate have better antimicrobial properties against Staphylococcus aureus than Pseudomonas aeruginosa.The film has good sustained drug release performance.The drug release rate is faster in the first100 minutes and slower in the following 100 minutes after immersion in normal saline.After 72 hours immersion,the film can still maintain a certain antimicrobial activity against Staphylococcus aureus.3)PVC-1 film was prepared by EBD method,and PVC-1 film was scraped off to obtain PVC-1 powder.PVC-1 powder and its mechanical mixtures with mass such as ciprofloxacin were used as targets respectively,and then PVC-2 single-component film and ciprofloxacin/PVC-2 composite film were deposited by EBD method.Compared with PVC1 film,the dehydrochlorination process in PVC2 film is more complete,the desired graphite phase structure appears,and the wear resistance of PVC2 film is excellent.After heat treatment at different temperatures,polyene fragments grow and unsaturationdecreases.Ciprofloxacin/PVC2 composite film has excellent antimicrobial properties.The composite film deposited on titanium substrate has better antimicrobial properties against Staphylococcus aureus than Escherichia coli.