CAREER: Single Molecule AFM Tips

abstractcts - 0349228 c。这个CAREER提案概述了一种实用可靠的方法，用单功能分子修饰硅AFM尖端，用于纳米尺度的生物学研究，包括Taq DNA聚合酶的具体研究。额外的教育工作将集中在有机薄膜专题课程的开发上，并在本科有机化学课程中引入超分子化学。制造令人满意的AFM尖端仍然是实现AFM作为研究生物系统的超灵敏分析仪器的全部潜力的主要障碍。尽管先前的工作已经证明，AFM尖端可以用探针分子修饰，以检测它们与靶分子的相互作用，但大多数这些尖端与生物材料的相互作用是非特异性的，阻碍了特异性相互作用的可靠测量。此外，探针分子在尖端的数量、位置和活性常常使测量混淆，因为这些参数通常是未知的，不能精确控制。为了解决这些长期存在的棘手问题，本文提出了一种合理的方法来可靠地制备定义良好、高度特异性的AFM尖端。新策略包括用一层坚固的单层低聚乙二醇（OEG）涂层硅AFM尖端以抵抗非特异性相互作用，通过电化学反应选择性激活OEG涂层尖端的顶端，并通过树突分子将单个官能团引入激活区域，形成单分子AFM尖端（SMAT）。这些步骤的明智结合完全是独一无二的。相关的表面化学将探索使用一系列的硅衬底设计模拟硅AFM尖端。这些模型系统包括平面硅（111）和（100），多孔硅和硅纳米颗粒。将使用各种分析技术研究这些模型系统上一系列OEG膜的沉积和性质，特别是蛋白质电阻率。这些研究之后，将对OEG薄膜上的纳米级电化学反应和随后的衍生化进行检查。从这些研究中获得的见解将为实现目标提供有价值的见解。此外，该结果可能会使利用生物相容性硅器件的几个领域受益，例如硅基生物传感器和可植入微型器件。提出的研究的另一个目标是展示smat在Taq DNA聚合酶的机械特性研究中，甚至在DNA合成过程中。这项研究的结果将为理解DNA复制的保真度提供新的见解。使用单分子尖端和基因工程聚合酶，将生成定义良好的系统，用于可靠的拉拔实验。除了从拟议的研究中无疑会产生的教育效益外，该提案还寻求开发有机薄膜专题课程，这将为学生提供对这一不断扩大的跨学科研究领域的深入介绍。所涵盖的材料将使学生熟悉分子构建块的类型和为各种应用设计功能薄膜所需的原理。本课程将编写一个脚本，因为现有的相关文本重点有限。为方便不同背景和专业的学生学习，我们会采用“小组学习”的方法。另一项促进跨学科教育的努力是将超分子化学纳入有机化学入门课程。

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.