Research On Controlled Preparation And Biological Effects Of Tellurium Nanomaterials

In this paper,tellurium nanoparticles（TeNPs）with good photothermal properties were introduced into the spongy structure of chitosan（CS）to construct a composite hydrogel with good photothermal properties.The synergistic effect between CS’trapping effect on bacteria and TeNPs’photothermal effect showed obvious antibacterial effect on Escherichia coli and Staphylococcus aureus.Specific research contents are as follows:1.Synthesis and characterization of TeNPs.Firstly,the morphology of TeNPs was adjusted by adding inorganic salt or changing surfactant.Two kinds of TeNPs with different morphologies were synthesized.The first method was to prepare butterfly shaped tellurium nanoparticles（P-TeNPs）using Na₂TeO₃ as raw material and PVP as surfactant.In the second method,rice granular tellurium nanoparticles（C-TeNPs）were prepared by REDOX method with TeO₂ as precursor and CTAC as surfactant.TeNPs were characterized by transmission electron microscopy（TEM）,X-ray photoelectron spectroscopy（XRD）and X-ray diffractometer（XPS）.The two synthetic TeNPs can absorb in the range of 400～1000 nm,and have good response to 808 nm near infrared light.The particle size distribution of TeNPs was measured by dynamic light scatterer（DLS）.The results show that the TeNPs prepared by the two methods have high crystallinity and uniform size,and the P-TeNPs size is about 200～220 nm,and the stability is good.The size of C-TeNPs is about 50 nm,and the stability is poor.The photothermal conversion efficiency of P-TeNPs was 52.9%and that of C-TeNPs was 62.5%.2.Preparation and characterization of CS/TeNPs hydrogels.CS/TeNPs hydrogels were synthesized by bidirectional freezing method and characterized by scanning electron microscopy（SEM）.The porosity,swelling ratio,water absorption,moisture retention and photothermal properties of CS/TeNPs hydrogels were determined.The experimental results show that the composite hydrogel has good porosity and swelling property,the porosity is more than 75%,the water absorption rate is in the range of 12～14 times,the moisture retention is more than 200%after 16 hours,can provide continuous moist environment for the skin wound.The composite hydrogels also show good photothermal effect.3.Study on antibacterial properties of TeNPs and CS/TeNPs hydrogels.The antibacterial effects of two kinds of TeNPs on Escherichia coli,Staphylococcus aureus,Salmonella,Pseudomonas aeruginosa,methicillin-resistant Staphylococcus aureus and levofloxacin resistant Escherichia coli were investigated.The results showed that the antibacterial effect of P-TeNPs was better than that of C-TeNPs.The CS/TeNPs hydrogel platform with good antibacterial ability was constructed by introducing P-TeNPs with good antibacterial properties into the spongy structure of CS.CS/TeNPs hydrogels have good antibacterial properties.Through the synergistic effect of TeNPs photothermal effect and CS capture effect,CS/TeNPs hydrogels show obvious antibacterial effect on Escherichia coli and Staphylococcus aureus.