| 题名 | 成团泛菌IMH合成贵金属纳米颗粒及其应用研究 |
| 作者 | 刘文婧 |
| 学位类别 | 硕士 |
| 答辩日期 | 2015-05 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 景传勇 |
| 关键词 | 微生物合成纳米颗粒 贵金属 机制 应用 吸附 表面增强拉曼，biosynthesis nanoparticles noble metal mechanism application adsorption SERS detecation |
| 其他题名 | Microbial-mediated noble metal nanoparticles by Pantoea sp.IMH: synthesis and application |
| 学位专业 | 环境工程 |
| 中文摘要 | 微生物介导下的贵金属离子的还原生成纳米颗粒的过程机理及其应用研究是当今环境化学领域的热点问题，同时也是微生物与材料科学交叉学科的研究热点。揭示微 生物合成纳米材料的机制即生物矿化成贵金属纳米颗粒的机制成为该领域亟待解决的问题。同时，生物合成纳米材料具有良好的均一性、分散性、稳定性及含有生物 分子等优点使其在众多领域存在应用潜力。因此，本研究旨在探究成团泛菌IMH合成贵金属纳米颗粒的过程机制及其应用。 首先，利用菌株成团泛菌IMH合成了金、银、钯和硒纳米颗粒。应用高分辨透射电子显微镜-选区电子衍射-X射线能谱（HRTEM-SAED-EDS）、X 射线光电子能谱能谱分析（XPS）和X射线吸收近边结构（XANES）等多种表征技术对纳米颗粒的形貌、晶型及元素组成等信息进行表征，结果表明菌IMH 能够合成均匀的零价金属纳米颗粒。HRTEM、聚丙烯酰胺凝胶电泳(SDS-PAGE)和液相色谱-质谱/质谱联用（LC-MS/MS）实验表明金纳米颗 粒的表面包裹有一层生物膜，且生物膜的主要成分为膜蛋白，即所合成的金纳米颗粒为核壳结构。研究结果拓展了贵金属纳米颗粒微生物合成方法。 其次，研究了成团泛菌IMH还原金离子合成金纳米颗粒的机制。通过提取构成菌体的三种组分胞外分泌物（EPS）、细胞壁和原生质体，并进行金胁迫实验，证 明菌体的这三种组分均能够还原金离子并合成金纳米颗粒。进一步通过TEM观察细胞金胁迫过程的超薄切片推测纳米颗粒的细胞合成过程：金离子最先通过EPS 还原形成AuNPs；随后吸附于细胞壁表面上的Au（III）原位还原形成AuNPs；此外，通过细胞膜进入细胞质中的金离子能够在基因调控还原酶的作用 下被还原形成AuNPs。 金还原动力学过程的X射线近边吸收光谱（XANES）实验表明Au(III)在还原为Au(0)过程中，中间会先快速还原为Au(I)，后再还原为 Au(0)。对Au(III)不同胁迫时间的样品进行定量即时聚合酶链锁反应（Q-PCR）实验，结果表明，细胞的Fe、Co、Zn、Mo、Cu和As多 种金属抗性机制参与Au(III)抗性还原过程。本研究进一步完善微生物还原金纳米颗粒的机制，为微生物参与金的生物地球化学循环过程提供了直接证据，。 最后，应用傅里叶变换红外光谱（FTIR）和拉曼技术表征生物合成金纳米颗粒，说明生物合成金纳米颗粒的外壳含有众多有机官能团，能够提供大量吸附位点； 而内核金具有良好的表面增强拉曼散射（SERS）效应，能够用作SERS检测基底。吸附试验表明生物合成金纳米颗粒对四种染料分子的吸附能够在2 min 内达到吸附平衡，其对阳离子型染料结晶紫、孔雀石绿和罗丹明6G的最大吸附率分别能够达到98.3%，59.2% 和97.7%，但对阴离子型染料刚果红的最大吸附率仅为3.6%。对阳离子型和阴离子型染料分子的吸附差异是由于金纳米颗粒的表面带负电。SERS检测试 验表明，以微生物合成金纳米颗粒作为SERS基底，对上述四种染料分子的检测限可达到10-6 M，因此生物合成金纳米颗粒能够应用于染料分子的检测。研究结果表明生物合成金纳米颗粒在有机染料分子等污染物的吸附去除和SERS检测方面具有应用前景。 |
| 英文摘要 | The formation, process and application of microbial- mediated noble metal nanoparticles have been the hot issues in the environmental chemistry field. And reaserch on biosynthesis nanoparticles is also the focus problem in the interdispline of microorganism and materials science. Until now, the mechanism of biosynthesis noble metal nanoparticles is not clear. Therefore, how microbe regulates noble metal ions and formed nanopaticles becomes an important issue. Meanwhile, biosynthesis nanoparticles with great applied potential need to be further explored. The aims of the present work were to explore the process, mechanism and application potential of biosynthesis noble metal nanoparticles by Pantoea sp.IMH. Firstly, AuNPs, AgNPs, PdNPs and SeNPs were synthesized by Pantoea sp.IMH. The results of high-resolution transmission electron microscope-selected area electron diffraction-energy dispersive spectroscopy (HRTEM-SAED-EDS), scanning electron microscope(SEM) and X-ray absorption near edge structure (XANES) provided complementary identification and characterization of biosynthesis metal nanoparticles and demonstrate the formation of uniform zero-valent metal nanoparticles in the medium. The existence of biolayer on the AuNPs was confirmed, resulting in the formation of Au@biolayer core-shell nanoparticles, and the biolayer was mainly comprised of membrane protein. This work expanded the methods of noble metal nanoparticles biosynthesis. Secondly, the biosynthesis gold nanoparticles mechanism was investigated. The experiments of bacterium components extration and Au(III) stress demonstrate that extracellular polymeric substances(EPS), cell wall and protoplast could reduce Au(III) and synthesis AuNPs. TEM experiment of continuous thin section samples in the bioreduction process suggested the biosynthesis AuNPs mechanism. And XANES results shows that in the reduction process, Au(III) was rapidly reduced to Au(I), and further reduced to Au(0). Q-PCR experiments of samples with different Au(III) exposure time demonstrated that the resistant gene clusters of Fe, Co, Zn, Mo, Cu and As in the strain IMH involved in Au(III) resitance and bioreduction process.. Our results shed a light on the mechanism of biosynthesis AuNPs mechanism. Finally, FTIR results show that the shell of biosynthesis AuNPs was composed of organic groups, which could provide numerous adsorption sites. And Raman results indicate that the core-AuNPs were SERS-active. Furthermore, the adsorption and SERS experiments demonstrate that biosynthesis core-shell AuNPs could efficently and rapidly remove dyes, and could used as substrate in SERS detection of dyes. Therefore, biosynthesis AuNPs open a new way in the removal and SERS detection of organic pollutants such as dyes. |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.rcees.ac.cn/handle/311016/34504]  |
| 专题 | 生态环境研究中心_环境化学与生态毒理学国家重点实验室 |
| 推荐引用方式 GB/T 7714 | 刘文婧. 成团泛菌IMH合成贵金属纳米颗粒及其应用研究[D]. 北京. 中国科学院研究生院. 2015. |
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