CAREER: Single Molecule AFM Tips

职业：单分子 AFM 技巧

• 批准号: 0349228
• 负责人: Chengzhi Cai
• 金额: $ 40万
• 依托单位: University of Houston
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0349228&HistoricalAwards=false
• 关键词: CAREER; Single; Molecule; AFM; Tips

AbstractCTS-0349228C. Cai, University of HoustonThis CAREER proposal outlines the development of a practical and reliable method to modify silicon AFM tips with single functional molecules for biological research at thenanoscale, including the specific study of Taq DNA polymerase. Additional educational efforts will focus on the development of a special topics course on Organic Thin Films, and the introduction of Supramolecular Chemistry to the undergraduate Organic Chemistry curriculum.The fabrication of satisfactory AFM tips remains a major obstacle to realizing the full potential of AFM as an ultra-sensitive analytical instrument for studying biological systems. Although previous work has demonstrated that AFM tips can be modified with probe molecules to detect their interaction with target molecules, most of these tips interact non-specifically with biomaterials, hindering the reliable measurement of specific interactions. Moreover, the number, location, and activity of probe molecules at the tip apex often confound the measurements, since these parameters are usually unknown and cannot be precisely controlled. To resolve these longstanding formidable issues, a rational approach to the reliable preparation of well-defined, highly specific AFM tips is proposed herein. The novel strategy involves coating silicon AFM tips with a robust monolayer of oligo(ethylene glycol) (OEG) to resist non-specific interactions, selectively activating the apex of the OEG-coated tips by electrochemical reactions, and introducing a single functional group via a dendron molecule to the activated area to form a single-molecule AFM tip (SMAT). The judicious confluence of these steps is entirely unique.Relevant surface chemistry will be explored using a series of silicon substrates designed to mimic silicon AFM tips. These model systems include flat silicon (111) and (100), porous silicon, and silicon nanoparticles. The deposition and properties, especially the protein resistivity, of a series of OEG films on these model systems will be studied using a variety of analytical techniques.These studies will be followed by the examination of nanoscale electrochemical reactions on the OEG films and subsequent derivatization. The insights gained from these studies will provide valuable insight for achieving the targeted objective. Furthermore, the results will likely benefit several fields that utilize biocompatible silicon devices, such as silicon-based biosensors and implantable microdevices.An additional goal of the proposed research is to showcase SMATs in the study of the mechanical properties of Taq DNA polymerase, even during DNA synthesis. The results from this study should provide new insight toward understanding the fidelity of DNA replication. Using single-molecule tips and genetically engineered polymerases, well-defined systems will be generated for reliable pulling experiments.In addition to the educational benefits that will undoubtedly arise from the proposed research, this proposal seeks also to develop a special topics course on Organic Thin Films, which will provide students with an in-depth introduction to this ever-expanding interdisciplinary field of research. The material covered will familiarize the students with the types of molecular building blocks and principles needed to design functional thin films for a variety of applications. A script will be written for this course, since existing related texts have limited focus. To facilitate learning among students with diverse backgrounds and expertise, the "group learning" technique will be adopted. An additional effort to promote interdisciplinary education is the incorporation of Supramolecular Chemistry into Introductory Organic Chemistry.

摘要CTS-0349228 C。Cai，University of Houston这份CAREER提案概述了一种实用可靠的方法的发展，该方法用单功能分子修饰硅AFM针尖，用于纳米尺度的生物研究，包括Taq DNA聚合酶的具体研究。另外的教育工作将集中在有机薄膜的专题课程的开发，并引入超分子化学本科有机化学courses.The令人满意的AFM针尖的制造仍然是一个主要的障碍，实现原子力显微镜作为研究生物系统的超灵敏分析仪器的全部潜力。 虽然以前的工作已经证明，AFM提示可以修改与探针分子，以检测其与目标分子的相互作用，这些提示大多数非特异性与生物材料的相互作用，阻碍了可靠的测量特定的相互作用。此外，探针分子在尖端顶点处的数量、位置和活性常常混淆测量，因为这些参数通常是未知的并且不能精确控制。为了解决这些长期存在的难题，本文提出了一种合理的方法来可靠地制备定义明确、高度特异性的AFM针尖。新的策略包括涂层硅原子力显微镜针尖与一个强大的单层低聚乙二醇（OEG），以抵抗非特异性相互作用，选择性地激活顶点的OEG涂层尖端的电化学反应，并引入一个单一的功能基团通过树枝状分子的激活区域，形成一个单分子原子力显微镜针尖（SMAT）。这些步骤的巧妙融合是完全独特的。相关的表面化学将使用一系列硅衬底来模拟硅原子力显微镜针尖。这些模型系统包括平面硅（111）和（100）、多孔硅和硅纳米颗粒。在这些模型系统上的一系列OEG膜的沉积和性质，特别是蛋白质电阻率，将使用各种分析技术进行研究。这些研究将通过检查OEG膜上的纳米级电化学反应和随后的衍生化进行。从这些研究中获得的见解将为实现预定目标提供宝贵的见解。此外，这些结果可能会有利于几个领域，利用生物相容性硅器件，如硅基生物传感器和植入式microdevices. A的另一个目标，拟议的研究是展示SMATs的Taq DNA聚合酶的机械性能的研究，即使在DNA合成。这项研究的结果应该为理解DNA复制的保真度提供新的见解。 使用单分子探针和基因工程聚合酶，将产生明确的系统，用于可靠的拉伸实验。除了拟议的研究无疑将产生的教育效益外，该提案还寻求开发一门关于有机薄膜的专题课程，为学生提供深入介绍这一不断扩展的跨学科研究领域。所涵盖的材料将使学生熟悉设计各种应用的功能薄膜所需的分子构建块和原理的类型。本课程将编写一个脚本，因为现有的相关文本的重点有限。为促进不同背景和专长的学生学习，将采用“小组学习”的方法。促进跨学科教育的另一项努力是将超分子化学纳入有机化学导论。