New Probes and Reagents for AFM Studies

用于 AFM 研究的新探针和试剂

• 批准号: 6518997
• 负责人: JOHN F KEANA
• 金额: $ 26.25万
• 依托单位: UNIVERSITY OF OREGON
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-01 至 2004-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6518997
• 关键词: amyloid proteins; atomic force microscopy; bioengineering /biomedical engineering; bioimaging /biomedical imaging; biomedical equipment development; chemical synthesis; image enhancement; immobilized enzymes; membrane proteins; molecular site; nanotechnology; reagent /indicator; technology /technique development

DESCRIPTION: (Applicant's Descritpion) Atomic force microscopy (AFM) is a powerful, relatively recent and rapidly expanding molecular imaging technique of broad applicability. AFM is providing for the first time images of individual biomolecules in their native state in aqueous solution. Important biological events in real time may be imaged by AFM. These include time lapse images of the assembly and deposition of amyloid fibrils, a process central to the onset of fatal diseases such as Alzheimer's disease. Nearly all type II diabetes mellitus patients have cytotoxic pancreatic amyloid, the formation of which is thought to be directly related to the development of the disease. In AFM, the sample is placed on an atomically flat surface such as freshly cleaved mica and is raster scanned by a sharp tip mounted at the end of a flexible cantilever. Resolution for biological specimens is typically 50-100 Angstroms and is limited by the sharpness of the tip. The sharpest tips available commercially for tapping mode AFM have a radius of approximately 4-50 nm. Recently, single walled carbon nanotubes were attached to AFM tips and show the best combination of' aspect ratio (tip height/base) and sharpness (approximately 3 nm) reported to date. The long term objective of this research program is to enhance the capabilities of AFM by providing a series of novel, molecularly sharp tips designed to improve the resolution of AFM images, i.e. the level of detail one can observe, without the need for highly specialized equipment. This proposal builds on the successful modular synthesis of prototype tip molecules during the first two years of the project. The synthetic tips have a broad base designed to attach chemically to a commercial tip so that only a single molecule can fit on the outermost part of the tip. The synthetic tips taper to a single atom or functional group designed to probe the sample. Prototype synthetic tip molecules prepared in our laboratory are themselves visible using conventional AFM, demonstrating the rigidity and robustness of the molecules. One aim is to synthesize new tip molecules with increased breadth of the base and height. These will be imaged by conventional AFM to determine the best synthetic building blocks to use in terms of rigidity. Another aim is to develop methodology for attaching the new tips to a conventional tip and to determine the resolution provided by the new synthetic tips. The tips are designed so that the functional group probing the sample can be changed. For example, a single biomolecule, e.g. an antibody, may be attached and used to probe the sample. The concept of an AFM label will be developed. The significance lies in the enhanced resolution that should be obtainable with the new synthetic tips.

描述：（申请人的描述）原子力显微镜（AFM）是一种 强大的，相对较新的和迅速扩展的分子成像技术 具有广泛的适用性。AFM首次提供了 在水溶液中处于其天然状态的单个生物分子。重要 真实的生物事件可以通过AFM成像。其中包括时间流逝 淀粉样纤维的组装和沉积的图像，这是一个核心过程， 老年痴呆症等致命疾病的发病。几乎所有II型 糖尿病患者胰腺有细胞毒性淀粉样蛋白， 这被认为与疾病的发展直接相关。在 在AFM中，将样品放置在原子级平坦的表面上，例如新鲜切割的表面。 云母，并通过安装在柔性 悬臂生物样本的分辨率通常为50 - 100埃 并且受到尖端的锋利度的限制。可用的最尖锐的提示 商业上用于轻敲模式的AFM具有大约4 - 50 nm的半径。 最近，单壁碳纳米管被附着到AFM针尖上，并显示出 纵横比（尖端高度/基部）和锐度的最佳组合 （约3 nm）。这项研究的长期目标是 计划是通过提供一系列新颖的， 分子尖锐的尖端，旨在提高AFM图像的分辨率，即， 一个人可以观察到的细节水平，而不需要高度专业化的 设备.这一建议建立在成功的模块化综合的基础上， 在项目的头两年，我们制作了尖端分子的原型。的 合成尖端具有宽的基部，其被设计成以化学方式附着到商业上， 尖端，使得只有单个分子可以适合尖端的最外部分。 合成尖端逐渐变细到单个原子或功能团， 示例.我们实验室制备的原型合成尖端分子是 使用传统的AFM，它们本身是可见的，证明了刚性和 分子的鲁棒性。一个目标是合成新的尖端分子， 增加了底座的宽度和高度。这些将通过常规的 原子力显微镜，以确定最佳的合成积木使用方面， 刚度另一个目标是开发将新尖端附着到 传统的尖端，并确定新的合成提供的分辨率 提示.探针头的设计使得探测样品的官能团可以 被改变例如，单个生物分子，例如抗体，可以是 用来探测样本AFM标签的概念将是 开发其意义在于， 可以用新的合成尖端获得。