【作者】 何娉婷；

【导师】 陶杰；

【作者基本信息】 南京航空航天大学 ， 材料加工工程， 2012， 博士

【摘要】 纳米TiO₂的应用领域越来越广泛，该材料在其生产和使用过程中不可避免的会与生物系统和生态环境接触，由此将可能对人体及生物产生影响。本文系统研究并分析了TiO₂纳米粒子和纳米管的体内和体外生物毒性、对原核微生物的抗性和作用机理、以及纳米TiO₂光催化抗菌剂在抗菌复合材料中的抗菌性能及抗菌机理。主要研究工作包括下列内容：（1）采用水热法制备了TiO₂纳米粒子和TiO₂纳米管，通过透射电镜（TEM）、X射线衍射仪（XRD）、傅立叶红外光谱分析仪（FT-IR）和拉曼光谱仪（Raman）等方法对制得的粉体进行了微结构表征。结果表明，TiO₂纳米粒子的粒径为100nm，TiO₂纳米管的管径为10nm，管长200nm左右，XRD显示TiO₂纳米粒子为锐钛矿型结构，而TiO₂纳米管为锐钛矿和金红石的混合晶型，红外光谱结果表明纳米TiO₂表面无其它修饰基团。（2）用气管滴注法对小鼠分别进行了TiO₂纳米粒子和纳米管染毒，在不同的时间对小鼠肺泡灌洗液、血清酶学指标检测和肺组织切片病理观察，结果表明两种材料均对肺脏组织产生损伤，但是从肺泡结构的完整性以及组织变厚的程度看，在相同剂量下纳米粒子组比纳米管组的危害更严重，引起肺组织细胞膜的损伤和脂质过氧化程度升高，肺部毛细血管的屏障作用未受到大的影响；这种染毒方式对小鼠肝脏、心肌组织、肾脏都产生不同程度的损伤。（3）通过小鼠腹腔巨噬细胞分别与TiO₂纳米粒子和纳米管直接接触染毒，观察不同时间巨噬细胞的形态，检测细胞的存活率以及细胞上清液中MDA，LDH，GSH的含量以评价TiO₂纳米粒子和纳米管的体外细胞毒性。研究结果表明：TiO₂纳米粒子能被巨噬细胞吞噬，对巨噬细胞形态有明显的影响，在不同染毒时间内对巨噬细胞造成急性损伤作用程度不同，存在着浓度-效应关系；TiO₂纳米管不能被巨噬细胞吞噬，对巨噬细胞形态影响并不明显；TiO₂纳米粒子和TiO₂纳米管接触培养的细胞上清液中MDA，LDH，GSH的变化均随染毒时间和浓度而改变，可见TiO₂纳米粒子和TiO₂纳米管均导致了细胞氧化应激并因此产生毒性损伤。（4）考察TiO₂纳米粒子和纳米管在无光照条件下的抗菌性能，结果发现在相同剂量、相同的接触时间，对大肠杆菌（Escherichia coli）和金黄色葡萄球菌（Staphylococcus aureus）TiO₂纳米粒子比纳米管具有更好的抗菌性能。因此，采用溶胶凝胶法制备了平均粒径为30nm氮掺杂TiO₂纳米粒子。比较了未掺杂二氧化钛纳米粒子和氮掺杂二氧化钛纳米粒子在黑暗条件和可见光照射条件下分别对大肠杆菌和金黄色葡萄球菌的影响，结果发现：大肠杆菌和金黄色葡萄球菌分别与二氧化钛纳米粒子接触培养2小时后，其在黑暗条件下的存活率均高于其在光照条件下的存活率，但未掺杂二氧化钛纳米粒子的存活率下降值远小于氮掺杂二氧化钛纳米粒子的存活率下降值，说明可见光照射对氮掺杂纳米二氧化钛的杀菌率有明显增强作用。（5）将制得的氮掺杂的二氧化钛纳米粒子作为抗菌剂，加入PP复合材料中，采用熔融共混法制得TiO₂纳米粒子不同含量的PP复合材料，对所制备的不同含量TiO₂纳米粒子的PP复合材料的微观结构、力学性能以及抗菌性能进行测试。结果表明：当TiO₂含量为2wt.%时，纳米TiO₂/PP复合材料的综合力学性能最好；纳米TiO₂/PP复合材料的冲击断口形貌为脆性断口，纳米TiO₂添加到PP中可提高复合材料的力学性能；抗菌性能测试发现，与纯PP材料相比，纳米TiO₂/PP复合料在光照条件下的抗菌性能明显优于纯PP材料。本文的上述研究结果进一步揭示了纳米TiO₂材料的生物毒性、光催化杀菌性能及其机理，对于评价纳米材料的环境和健康风险，保证纳米技术产业的可持续的发展具有理论指导意义，为进一步研究具有广泛应用前景的聚合物基纳米抗菌复合材料的工作奠定了一定的理论基础，积累了一些实验经验。更多还原

【Abstract】 TiO₂nanomaterials were applied widely in various fields nowadays. TiO₂nanomaterials wouldbring more and more healthy and ecological damages to the society owing to the extensive andinevitable contact with biological systems and environment. In this study, we systematicallyinvestigated the TiO₂nanoparticles and nanotubes in vivo and in vitro biological toxicity as well as onprokaryotic microbial resistance and their mechanisms, and a further research on the antibacterialproperties and antibacterial mechanism of TiO₂nanoparticles as photocatalytic antibacterial agents inPP composite materials was carried out.The research work mainly includes the following aspects:（1） TiO₂nanoparticles and TiO₂nanotube samples were prepared by hydrothermal reaction andcharacterized by means of transmission electron microscope （TEM）, X ray diffraction （XRD）, Fouriertransformed infrared spectrum （FT-IR） and Raman spectrum （Raman）, respectively. The resultsshowed that the diameters of as-prepared nanoparticles and nanotubes were about50nm and10nmwith about200nm in length. The crystal form of TiO₂nanoparticles were homogeneous anatase andTiO₂nanotube was mixed crystal with anatase and rutile. And the other modification groups were notfound on the surface of nano TiO₂.（2） The biological toxicity of TiO₂nanoparticles and TiO₂nanotubes in vivo was studied. Micewere exposed to TiO₂nanomaterials through intratracheal instillation, and then at different time themurine bronchoalveolar lavage fluid and serum indexes in blood were detected and the pathologicalmorphology of lung tissue were observed. The results showed that lung tissue damages were led bytwo different shape TiO₂nanomaterials. From the alveolar structure integrity of lung as well as thedegree of the abnormal tissue thickening, the responds to the same dose nanoparticles group weremore serious than to the nanotube group. And the lung tissue cell membrane damage and lipidperoxidation increased, but the barrier effect of lung capillary wasn’t affected. There were differentdegrees damage to liver, kidney and myocardium.（3） The cytotoxicity on mouse peritoneal macrophages of TiO₂nanoparticles and nanotubes invitro was studied at different contacted time. The morphology of macrophages was observed, the cellsurvival and the activity of enzyme in cell supernatants were detected. The results showed that TiO₂nanoparticles could be engulfed by macrophage and have obvious effects on the morphology ofmacrophages. The degrees of acute and injury effects on macrophages were concentration dependentin different contamination time. The TiO₂nanotubes could not be engulfed by macrophage and the effects on macrophage morphology was not apparent. The enzyme activity in TiO₂nanoparticles andTiO₂nanotube contacted cultured cell supernatants changed with contamination time andnanomaterials concentration, which led to cellular oxidative stress to produce toxic injury, inducedfree radical and enhanced oxidative stress ability.（4） The antibacterial property of TiO₂nanoparticles and nanotubes was investigated in theabsence of light. It was found that TiO₂nanoparticles have higher antibacterial activity than nanotubeson Escherichia coli and Staphylococcus aureus at the same dose and contacted time, but theantibacterial ratio was low. In order to get more high antibacterial activity and respond to visible light,nitrogen doped TiO₂particles were prepared by the sol-gel method. The average diameter ofnanoparticle was about30nm. Comparing the antibacterial activity of undoped titanium dioxidenanoparticles with nitrogen doped titanium dioxide nanoparticles in the dark and visible lightirradiation conditions on Staphylococcus aureus and Escherichia coli, the survival rates of the bacteriacontacted with nanoparticles for2hours in the dark conditions were higher than that underillumination conditions, but the survival rate value drop rate for not doped titanium dioxidenanoparticles from the dark to illumination conditions was far less than that for nitrogen doped titaniananoparticles at the same contacted time. This illustrated that the visible light irradiation enhanced theantibacterial activity of nitrogen-doped nano titanium dioxide.（5） TiO₂/PP composite materials with different contents of nitrogen doped titanium dioxidenanoparticles were manufacted by melt blending method. The mechanical properties, antibacterialperformance and microstructure of TiO₂/PP composite materials were performaced.The resultsshowed that TiO₂nanoparticles aggregated into microparticles in TiO₂/PP composite materials. Themechanical properties and antibacterial performance of the composites were better as the TiO₂contentis2wt%.Through this research, the biological toxicity and photocatalytic bactericidal performance ofnano TiO₂were explained further, and the experimental and theoretical foundation were laid for a newenvironment purification composite materials research. And this research had very importantsignificance for evaluating nanomaterials potential environment risks and ensuring thenanotechnology industry sustainable development.更多还原