【作者】 李永仙；

【导师】 冯威；

【作者基本信息】 大连海事大学 ， 环境科学， 2008， 硕士

【摘要】 纳米科学与信息科学和生命科学并列,已经成为21世纪的三大支柱科学。由于纳米材料独特的物理化学性质（量子尺寸效应、小尺寸效应、界面与表面效应和量子隧道效应等）,使得纳米颗粒具有不同于体相物质的优质性能,广泛的应用于各种生产活动中,进入人们的生活。这些具有独特物理化学性质的纳米材料,对人体健康及环境将带来潜在影响,目前已经引起科学界,乃至政府部门的广泛关注。文中从小球藻生长情况及其微观结构方面研究了两种不同粒径（20 nm和7nm）的NiO纳米颗粒对小球藻的胁迫性,并与镍离子进行了对比研究。概率单位法计算得NiO纳米颗粒（20 nm）对小球藻96 h的EC₅₀为31.4 mg/L,NiO纳米颗粒（7 nm）对小球藻96 h的EC₅₀为52 mg/L,而镍离子对小球藻96 h的EC₅₀为1.73 mg/L。利用扫描电镜（SEM）、透射电镜（TEM）研究了受不同粒径NiO纳米颗粒和镍离子胁迫前后小球藻细胞微观结构的变化。受NiO纳米颗粒（20 nm和7 nm）胁迫后,叶绿体只是部分受损,导致光合作用受阻,合成代谢减慢。藻液颜色变浅,再经过适当长时间后,小球藻液颜色是可以恢复的。受镍离子胁迫的小球藻,叶绿体中类囊体受损,有的甚至消失,使得叶绿素含量降低,光合作用明显下降,生长受到严重抑制。由此得出,NiO纳米颗粒的毒性远小于镍离子,NiO对小球藻的胁迫性是可以恢复的。7 nm的NiO纳米颗粒对小球藻的毒性稍小于20 nm的NiO颗粒。本文同时还研究了小球藻与NiO纳米颗粒之间的生物界面转化效应,借用X-射线分析仪（XRD）、X-光电子能谱仪（XPS）和高分辨透射电镜（HRTEM）分析了NiO纳米颗粒与小球藻细胞作用前后镍元素价态的变化,经检测有单质镍存在,说明小球藻细胞中的某些物质与NiO（镍为二价）发生了化学反应,将二价镍还原成零价镍,其作用机制还有待进一步的研究。更多还原

【Abstract】 Nano-science,information science and life science have become the three main science fields in the 21th century.Because of the special physical and chemical properties（Quantum Size Effect,Small Size Effect,Quantum Tunnel Effect,Interface and Surface Effect）,the nanoparticles have the high quality different from normal substances,and widely be applied to produce activities.Then they can be exposed to people.There is the potential impact to environment and people health,and this effect has attracted worldwide attention of scientific community and government.Growth conditions and micro-morphology are studied to reveal the inhibition of NiO nanoparticles（20 nm and 7 nm） to chlorella sp.,by contrast with Ni²⁺.The EC₅₀ value of NiO nanoparticles（20 nm） to chlorella sp.at 96 h is 31.4 mg/L by probability unit method,the NiO nanoparticles（7 nm） is 52 mg/L,but the EC₅₀ value of Ni²⁺ was 1.73 mg/L in the same conditions.The cell micro-morphology of chlorella sp.inhibited by NiO and Ni²⁺ were observed by Scanning Electron Microscopy（SEM） and Transmission Electron Microscopy（TEM）.The chlorella sp.cell inhibited by the NiO （20 nm and 7 nm）,the chloroplasts partly destroyed,photosynthesis hindered and anabolism slowed.The solution of chlorella sp.become light,after a proper long time, the color of the solution can be recovered.But the chlorella sp.inhibited by Ni²⁺,the chloroplast thylakoids are destroyed,some disappeared and the content of chlorophyll decreased,result in the decrease of photosynthesis and the great inhibition of cell growth.The nuclear membrane disrupted,some even disappeared.The nucleoli also disappeared.The results show that Ni²⁺ is far more toxic than NiO and the toxicity of 7 nm NiO is less toxic than that of 20 nm NiO.The biological transform between chlorella sp.and NiO nanoparticles is studied. The valence change of nickel is analyzed by using XRD,HRTEM and XPS.This shows that there is simple substance of nickel after the reaction between chlorella sp.and NiO nanoparticels,and it may deduce that the NiO nanoparticles react redox with certain organs of the chlorella sp..The further research of mechanism is expected.更多还原