CARBON NANOTUBES AS KNIVES FOR CUTTING VITREOUS ICE

碳纳米管作为切割玻璃冰的刀具

• 批准号: 7597301
• 负责人: John RICHARD MCINTOSH
• 金额: $ 1.15万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7597301
• 关键词: Biological; Carbon Nanotubes; Cells; Cellular Structures; Computer Retrieval of Information on Scientific Projects Database; Condition; Decompression Sickness; Devices; Diamond; Electron Microscope; Electrons; Freezing; Funding; Grant; Hardness; Ice; Institution; Measures; Methods; Micromanipulation; Microtomy; Numbers; Object Attachment; Problem Solving; Process; Relative (related person); Research; Research Personnel; Resources; Sampling; Scanning; Slice; Source; Stretching; Temperature; Thick; Tungsten; United States National Institutes of Health; Viscosity; Welding; Work; base; desire; millimeter; radius bone structure; reconstruction; research study

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Tomographic reconstruction of frozen-hydrated biological samples, embedded in amorphous ice, is a powerful method for the study of cell structure in its initially native condition. However, few biological samples are less than 0.5 micrometers along the beam axis, thin enough to be viewed in their entirety with 300 KeV electrons. It is therefore important to develop methods for slicing cells while they are frozen. A diamond knife in a good cryo-ultramicrotome can cut the desired sections without warming them to temperatures at which amorphous ice will crystallize, but stable diamond knives are thick (the angle included at the knife edge is 25-35 degrees), so the amorphous ice is usually compressed and sharply bent by the cutting process. To solve these problems we are investigating the use of carbon nanotubes (CNTs) as devices that could be used as tight wires to sever thin slices from a block of vitrified biological material. Single walled CNTs have a radius of about 1 nm, less then the curvature at the edge of a sharp diamond knife. CNTs can be millimeters long and are known to be strong, but how strong relative to amorphous ice remains to be determined. We have examined commercially obtained and homegrown CNTs in a scanning electron microscope, disentangled from their neighbors by micromanipulation. We stretch them over a thin loop of tungsten wire and have developed a "welding" process that forms a strong bond between the CNT and the tungsten. We are working to streamline this process so it can be used to make useful numbers of CNT-based cutting devices. We are also experimenting with devices that can measure the hardness and viscosity of vitreous ice, so we can understand the physical requirements for the microtomy we plan.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 嵌入无定形冰中的冷冻水合生物样品的层析成像重建是研究其最初天然状况的细胞结构的强大方法。 但是，很少有生物样品沿着梁轴小于0.5微米，足够薄，可以用300 keV电子全部观看。 因此，重要的是在冷冻时开发切片细胞的方法。 良好的冷冻粉状刀片中的钻石刀可以切割所需的部分，而无需将它们温暖到无定形冰会结晶的温度，但是稳定的钻石刀厚度（刀边缘的角度为25-35度），通常压缩并通过切割弯曲的过程被压缩并尖锐的冰层。 为了解决这些问题，我们正在研究使用碳纳米管（CNT）作为可以用作紧密电线的设备，以从一块玻璃化的生物材料中切断薄片。 单壁CNT的半径约为1 nm，少于锋利的钻石刀边缘的曲率。 CNT可以是毫米长的，并且已知强度很强，但是相对于无定形冰的强度仍然有待确定。 我们已经在扫描电子显微镜中检查了商业上获得的CNT，并通过微观渗透从邻居那里解散。我们将它们延伸到钨丝电线的细环上，并开发了一个“焊接”过程，该过程形成了CNT和钨之间的牢固键。 我们正在努力简化此过程，因此可以用来制作有用的基于CNT的切割设备。 我们还正在尝试可以测量玻璃冰的硬度和粘度的设备，因此我们可以了解计划的微切开术的物理要求。