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。这一过程既耗时又昂贵。包含微悬臂传感器阵列的便携式设备能够一次检测多种分析物，有一天，可以用于现场对水中进行完整的重金属分析，快速，成本有效，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50微米，厚1微米，可以接收特定的目标分析物。由于它们的尺寸小，数百个悬臂可以合并在一角硬币大小的区域内。尽管悬臂式传感器提供了满足上述目标的所有必要标准，但其可重复性使其无法应用于商业设备。本应用程序的主要目的是通过实验观察和数值建模和模拟的创新结合来研究影响悬臂式传感器再现性的因素：探索材料科学问题，例如用于锚定传感层的Au薄膜的形态；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；研究了新型杯芳烃传感层的主客体反应，用于检测特定重金属。

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.