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Characterization, nanosafety, and cellular imaging of carbon nanotubes.

机译：碳纳米管的表征，纳米安全性和细胞成像。

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摘要

This dissertation presents three important contributions to the field of carbon nanotube (CNT) environmental health and safety (EH&S). The first concerns aqueous CNT samples purified by centrifugation, the importance of thorough CNT sample characterizations, and improving the comparability of CNT toxicity assessments. Herein, using carboxylated multi-walled CNTs (cMWCNTs) suspended in water without a surfactant, a Boehm titrimetric method was developed and used to show for the first time that the surface acidity of oxidized carbon materials in aqueous cMWCNT suspensions was enriched by ~40% by a single low-speed centrifugation step. This significant difference in surface acidity between un-centrifuged and centrifuged cMWCNT suspensions has not been previously appreciated and is important because the degree of surface acidity is known to affect the interactions of cMWCNTs with biological systems. The second concerns the lack of CNT exposure data from laboratories where dry CNT powders are handled, the need to fully understand CNT release scenarios to make accurate EH&S risk assessments and to implement effective control measures, and the lack of chemical specificity with the current suite of instrumentation used to monitor the release of CNTs in workplaces. Herein, the first demonstration of Raman spectroscopy to unequivocally identify whether particulate matter collected from a multi-user analytical balance workstation comprised CNTs is presented. The approach revealed CNT contamination at this workstation, led to the identification of the exact CNT products, the users who handled these CNTs, and an improved protocol for safely weighing CNTs. The third concerns the need to more thoroughly understand how macrophage cells, the primary responders to foreign particles, process the CNTs that they accumulate. Herein, the distribution of poloxamer-coated, pristine and carboxylated MWCNTs within murine RAW 264.7 macrophage cells is assessed using Raman microscopy to image MWCNTs and immunofluorescence microscopy to image phagolysosomes. In both cases, MWCNTs were observed to co-localize in phagolysosomes, which supports the hypothesis that these cells can accumulate MWCNTs by phagocytosis. This evidence has implications with respect to the proper functioning of phagolysosomes in maintaining cellular health, as well as, being able to rationally design novel approaches to remediate potential chronic toxicity by accumulated MWCNTs.
机译：本文对碳纳米管（CNT）环境健康与安全（EH＆S）领域提出了三个重要的贡献。第一个问题涉及通过离心纯化的水性CNT样品，全面表征CNT样品的重要性以及提高CNT毒性评估的可比性。在本文中，使用没有表面活性剂的悬浮在水中的羧化多壁碳纳米管（cMWCNT），开发了Boehm滴定法，并首次用于证明水性cMWCNT悬浮液中氧化碳材料的表面酸度增加了约40％通过一个低速离心步骤。未离心和离心的cMWCNT悬浮液之间表面酸度的这种显着差异以前尚未被认识到，这一点很重要，因为已知表面酸度会影响cMWCNT与生物系统的相互作用。第二个问题涉及缺乏处理干式CNT粉的实验室的CNT暴露数据，需要充分了解CNT释放情景以进行准确的EH＆S风险评估和实施有效的控制措施，以及目前的一套化学试剂缺乏化学特异性用于监测工作场所中碳纳米管释放的仪器。在此，首次展示了拉曼光谱法，以明确确定是否从包含CNT的多用户分析天平工作站上收集了颗粒物。该方法揭示了该工作站上的CNT污染，从而确定了确切的CNT产品，处理这些CNT的用户以及改进的安全称量CNT的协议。第三个问题涉及需要更彻底地了解巨噬细胞（异物的主要响应者）如何处理它们积聚的CNT。在本文中，使用拉曼显微镜对MWCNT进行成像，并通过免疫荧光显微镜对吞噬体进行成像，来评估在小鼠RAW 264.7巨噬细胞中泊洛沙姆包被的，原始的和羧化的MWCNT的分布。在这两种情况下，均观察到MWCNTs在吞噬体中共定位，这支持了这些细胞可以通过吞噬作用积累MWCNT的假设。该证据涉及吞噬溶酶体在维持细胞健康方面的正常功能，以及能够合理设计新方法以通过累积的MWCNT补救潜在的慢性毒性的影响。

著录项

  • 作者

    Braun, Elizabeth Irene.;

  • 作者单位

    The University of Texas at Dallas.;

  • 授予单位 The University of Texas at Dallas.;
  • 学科 Analytical chemistry.;Chemistry.
  • 学位 Ph.D.
  • 年度 2016
  • 页码 160 p.
  • 总页数 160
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 康复医学;
  • 关键词

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