Experimental and Numerical Studies of Cantilever Sensors

现有的检测淡水中重金属的方法需要收集样本并送到专门的实验室进行分析。这样的程序既耗时又昂贵。有一天，含有能够同时检测几种分析物的微悬臂传感器阵列的便携式设备可以用于现场对水进行完整的重金属分析，快速、经济有效，并且只需最少的用户培训。微悬臂传感器是一种小悬臂，长约400微米，宽约50微米，厚约1微米，功能齐全，可接受特定的目标分析物。由于它们的体积很小，数百个悬臂可以安装在一个一角硬币大小的区域内。虽然悬臂式传感器为实现上述目标提供了所有必要的标准，但它们的重复性阻碍了它们应用于商业设备。这项应用的主要目标是，利用实验观察与数值模拟和模拟的创新组合，通过以下方式调查影响悬臂式传感器重现性的因素：探索材料科学问题，如用于锚定传感层的薄Au膜的形貌；利用流体动力学模拟了解分析物如何在传感器单元内流动；以及研究用于检测特定重金属的新型杯芳烃传感层的主/客体反应。 拟议工作的结果将加快悬臂式传感器在商业设备中的应用，用于从检测病毒到跟踪爆炸装置气体的各种应用。了解材料科学问题将有助于各种传感器技术将化学或生物刺激转化为机械反应。随着淡水水源的污染继续增加，开发用于测量淡水中重金属水平的便携式设备的长期目标不仅将使加拿大受益，而且将使世界各国政府和环境保护机构受益。 作为第二个目标，将依靠我在扫描探针显微镜方面的专业知识，我们将努力成为第一个调查摩擦和摩擦老化新理论的有效性的人。摩擦和摩擦老化是材料的基本性能，具有从机械磨损到构造板块运动的深远影响。理解这些基本概念最终会导致控制它们的能力，这可能会在许多技术应用中产生重大影响，从开发更高效的发动机到更耐磨的工具。我们还将尝试开发一种新的理论来更好地解释动态力谱测量。如果成功，这项工作的结果将使人们能够以前所未有的精度测量分子和生物键的强度。

Existing methods for detecting heavy metals in fresh water require samples be collected and sent to specialized laboratories to be analyzed. Such a procedure is time consuming and expensive. Portable devices containing arrays of microcantilever sensors capable of detecting several analytes at one time could, one day, be used for performing a complete heavy metal analysis of water onsite, quickly, cost effectively, and with minimal user training. Microcantilever sensors are small cantilevers approximately 400 microns long, 50 microns wide, and 1 micron thick functionalized to be receptive to specific target analyte. Because of their small size, hundreds of cantilevers can be incorporated in an area the size of a dime. Although cantilever sensors offer all the necessary criteria for satisfying the above goal, their reproducibility has prevented them from being implemented into commercial devices. The principle objective of this application is to investigate, using an innovative combination of experimental observations and numerical modeling and simulations, the factors that affect the reproducibility of cantilever sensors by: exploring the materials science issues such as the morphology of the thin Au film used to anchor the sensing layer; understanding how analyte flows within the sensor cell using fluid dynamics simulations; and studying the host/guest reactions of new calixarene sensing layers designed to detect specific heavy metals. The results of the proposed work will quicken the application of cantilever sensors into commercial devices for a variety of applications from detecting viruses to trace gases from explosive devices. Understanding the materials science issues will benefit a variety of sensor technologies that translate a chemical or biological stimulus into a mechanical response. The long term objective of developing portable devices for measuring heavy metal levels in fresh water will not only benefit Canada but also governments and environmental protection agencies worldwide as the contamination of our freshwater sources continues to grow. As a second objective, which will rely on my expertise in scanning probe microscopy, we will endeavour to be the first to investigate the validity of new theories of friction and frictional aging. Friction and frictional aging are fundamental properties of materials with far reaching implications from machine wear to the motion of tectonic plates. Understanding these fundamental concepts ultimately leads to the ability to control them which could have significant implications in many technological applications from developing more efficient engines to more wear resistant tools. We will also attempt to develop a new theory to better interpret dynamic force spectroscopy measurements. If successful the results of this work will allow the strength of molecular and biological bonds to be measured with unprecedented accuracy.