Preparation And ApplIcation Of Functional Zinc OXide Nanoparticles And Their Composites

The treatment of bacterial infection has always been a challenge in clinical practice.With the discovery of antibiotics in the last century,people had a good way to cure wound infection.However,the overuse of antibiotics has led to the increase of drug-resistant strains,as a result,bacterial infections poses a serious threat to human health.The development of nanometer functional materials provides a new breakthrough to solve the increasingly serious problem of drug-resistant strains infection.Nanometer zinc oxide is widely used in the antimicrobial field due to its characteristics of small particle size and strong antibacterial activity.In this paper,three kinds of functional nanocomposites were developed using nano-sized zinc oxide as the substrate.The structure and properties of the composites were studied,and their inhibition ability against Staphylococcus aureus and Escherichia coli were evaluated.The following conclusions were drawn:1)ε-poly-L-lysine modified zinc oxide nanoparticles.In order to prevent zinc oxide nanoparticles from causing harm to normal cells during the antimicrobial process,the nanocomposites were designed by coating with ε-poly-L-lysine.Zinc oxide nanoparticles with size of about 4.9 nm were prepared by sol-gel method.After coating with ε-poly-L-lysine,the particle size was about 5.1 nm.The successful coating of ε-poly-L-lysine was verified by IR spectrum,X-ray diffraction and X-photoelectron spectroscopy.The thermogravimetric analysis showed that the proportion of ε-poly-L-lysine in the complex was 7.9%.Due to the presence of polydopamine,fluorescence spectra of Zn O which coated with ε-poly-L-lysine showed fluorescence quenching at 400-800 nm.The antimicrobial test results showed that the Zn O nanoparticles which coated with ε-poly-L-lysine showed good antimicrobial activity against E.coli and Staphylococcus aureus.The results of cell compatibility test showed that the biocompatibility of the Zn O nanoparticles which coated with ε-poly-L-lysine increased by about 2 times compared with Zn O nanoparticles at 500μg/m L.2)Preparation and application of Zn O nanoparticles/aramid nanofiber composites.Aramid nanofiber as a new type of nanomaterial,has been widely used in the field of biomedicine,but there are few researches on its antimicrobial properties at present.To solve this problem,the antimicrobial composites was prepared by vacuum assisted--filtration with high strength aramid nanofiber and zinc oxide nanoparticles.The results of infrared spectrum and X-ray diffraction show that the Zn O/aramid nanofiber composites have been successfully prepared.The results of UV-Vis spectrum show that the transmittance of the composite film is only 0.7% in the ultraviolet region,so it has good UV shielding performance.The mechanical properties test showed that the pure aramid nanofiber film had the strongest mechanical properties,while the mechanical properties of the composite film decreased with the increase of the content of Zn O nanoparticles,which may be due to the stress concentration caused by Zn O nanoparticles.The water contact Angle test results show that the hydrophobicity of the composite film is enhanced with the increase of zinc oxide content.The antibacterial test results showed that the composite membrane had inhibitory effect on Escherichia coli,and the inhibitory effect of the composite membrane on Escherichia coli was enhanced with the increase of the content of zinc oxide nanoparticles.When the content of zinc oxide nanoparticles was 20%,the composite membrane had the strongest inhibitory effect on Escherichia coli.3)Preparation and application of Zn O nanoparticles/carbon nanotubes composites.The multiplicity of antimicrobial materials makes it possible to combine many kinds of materials,and multi-walled carbon nanotubes have strong ability to adsorb bacteria,with zinc oxide nanoparticles were used for synergistic antimicrobial.The antimicrobial materials of Zn O/carbon nanotubes were prepared by mussel-inspired method.The results showed that the antimicrobial materials were successfully prepared by infrared spectrum and X-ray diffraction.The results of thermogravimetric analysis showed that the proportion of Zn O nanoparticles in the composite was 35.5%.The results show that the dispersion performance of the composite is significantly improved compared with that of muti-wall carbon nanotubes.The antibacterial test results showed that the survival rates of Escherichia coli and Staphylococcus aureus treated by the composite material were 5% and 0.2%,respectively.Compared to the multi-walled carbon nanotubes,the survival rates of the bacteria were significantly reduced when the concentration at 800 μg/m L,which proved that the composite material had stronger antibacterial activity.