Sensors: LiMo3Se3 Nanowires as Programmable Chemical Sensors

摘要CTS-0427418F。Osterloh，U of Cal Davis Sensors：LiMo3Se3纳米线作为可编程化学传感器提出了一种通用的电化学传感器，用于快速和选择性地检测化学战剂、葡萄糖、爆炸物以及气相和液态中的其他分子。该传感器是基于分散在两个或几个金电极之间的金属LiMo3Se3纳米线的纳米厚膜阵列。当暴露在溶剂蒸气中时，纳米线的导电性发生了巨大的(240%)和可逆的变化。电子反应取决于溶剂的性质和浓度，它发生在曝光的几秒钟内。纳米线的选择性可以通过将受体共价连接到纳米线的硒表面来控制。一旦连接上丙酸(一种质子受体)，纳米线膜就成为检测水溶液中质子的元件。通过将10 nm大尺寸的金纳米粒子连接到导线上，然后将3-巯基丙酸附着到金纳米粒子上，也形成了类似的pH传感器。为了将LiMo3Se3纳米线用于传感器，比基于传统材料的传感器更快、更小、更灵敏、更通用、更便宜，计划系统地研究LiMo3Se3纳米线在不同条件下的结构、物理和电学性质。纳米线对分子或可变电荷、极性和配位能力的电导响应将使用图案化的氧化铟锡微电极阵列来测量，该微电极阵列允许同时询问多达20种不同的纳米线薄膜。在特定条件下与纳米线相互作用的分子/离子的数量将通过石英晶体微天平测量来确定。将对具有小分子和寡肽的纳米线进行系统的共价修饰，以引入用于选择性检测化学战剂、葡萄糖和爆炸物的受体。对修饰纳米线的扫描隧道测量将探测由于这些修饰而发生的以及分析物相互作用引起的电子结构的变化。伴随着电子结构和分子动力学计算，将模拟观察到的现象，并开发模型来合理地解释影响。由于能够检测葡萄糖、爆炸物和化学战剂，本项目将制造的基于纳米线的传感器将直接为医疗保健和国家安全做出贡献。为了建立对分子-纳米线相互作用的物理和化学方面的分子水平的理解，这个项目也将对纳米线传感器的设计和理解产生普遍的影响。研究生和本科生将参与该项目的所有方面。他们将准备材料，并用他们独立操作的仪器对其进行表征，他们将在会议上展示他们的结果。与物理学家和理论化学家的合作以及与物理学家的合作将加强跨学科的交流。该项目的成果将被纳入当地科学博物馆的展品中，并被纳入校园和当地高中的化学演示节目中。这项K-12推广计划将涉及加州大学戴维斯分校化学俱乐部，这是一个由20名不同专业的本科生组成的组织，由PI监督。在开放的日子里，本科生将有机会参观实验室，并与各自的PI联系。将开设一门关于“无机胶体”的研究生课程，介绍胶体粒子的化学和物理及其在工程应用中的用途，特别是传感器技术。

AbstractCTS-0427418F. Osterloh, U of Cal DavisSensors: LiMo3Se3 Nanowires as Programmable Chemical SensorsA versatile electrochemical sensor for the rapid and selective detection of chemical warfare agents, glucose, explosives and for other molecules in the gas and liquid phases is proposed. The sensor is based on arrays of nanometer thick films of metallic LiMo3Se3 nanowires that are dispersed between two or several gold electrodes. Upon exposure to solvent vapors the nanowires undergo large (240%) and reversible changes of their conductivity. The electronic response depends on the nature of the solvent and on the concentration, and it occurs within seconds of the exposure. The selectivity of the nanowires can be controlled by covalently linking receptors to the selenide surface of the nanowires. Upon attachment of propionic acid (a proton receptor) the nanowire film becomes a detection element for protons in aqueous solution. A similar pH sensor also forms by linking 10 nm large gold nanoparticles to the wires, and by subsequently attaching 3-mercaptopropionic acid to the gold nanoparticles.In order to use the LiMo3Se3 nanowires for sensors that will be faster, smaller, more sensitive and versatile and less expensive than sensors based on conventional materials, it is planned to systematically study the structure, physical and electrical properties of LiMo3Se3 nanowires under variable conditions. The conductivity response of the nanowires to molecules or variable charge, polarity and coordinating power will be measured using patterned indium tin oxide microelectrode arrays that allow simultaneous interrogation of up to twenty different nanowire films. The number of molecules/ions that interact with the nanowires under given conditions will be determined with quartz crystal microbalance measurements. Systematic covalent modifications of the nanowires with small molecules and with oligopeptides will be conducted to introduce receptors for the selective detection of chemical warfare agents, for glucose and for explosives. Scanning tunneling measurements on modified nanowires will probe changes of the electronic structures that occur as a result of these modifications and that are due to analyte interactions.Accompanying electronic structure and molecular dynamic calculations will simulate the observed phenomena, and develop models to rationalize the effects.In being able to detect glucose, explosives, and chemical warfare agents, thenanowire based sensors that will be fabricated in this project will directly contribute to health care and national security. In establishing a molecular level understanding of the physical and chemical aspects of molecule-nanowire interactions this project will make also a general impact on the design and understanding of nanowire sensors.Graduate and undergraduate students will be involved in all aspects of the project. They will prepare the materials and characterize them with instruments that they operate independently, and they will present their results at conferences. Collaborations with physical and theoretical chemists and with a physicist will strengthen the communication across disciplines. Results from the project will be incorporated into exhibits at a local science museum and into chemistry demo shows on campus and at local high schools.This K-12 outreach initiative will involve the UC Davis chemistry club, an organization of 20 undergraduate students with different majors which is overseen by the PI. During an open door day undergraduate students will be given the opportunity to visit the lab and to make contact with the respective PIs. An graduate course on "Inorganic Colloids" will be offered as an introduction to the chemistry and physics of colloidal particles and their uses for engineering applications, and in particularly to sensor technology.