CAREER: Fundamental and Applied Studies of Novel Electrokinetic Effects

摘要CBET-0645097T。微流控设备有可能给化学、生物和医学带来革命性的变化，就像集成电路在计算、科学和技术方面所做的那样。先进的设备已经被开发出来，用来执行那些使用宏观技术将会更加昂贵、更加困难甚至不可能完成的任务。如果微流体流能以一种自给自足、便携的方式驱动，这样的设备就可以从实验室带到野外(或皮下)。电动流动对微流体的便携性具有许多优势，然而，到目前为止，基本问题阻碍了它们在实际系统中的应用。这份职业建议书描述了一个具有两个中心目标的理论和实验计划：1)对液/液界面上的电渗透流动有一个基本的了解，以及2)利用这些现象和相关现象来开发真正的便携式微流体操纵系统。为了实现第一个目标，PI将开发和使用微流体系统，该系统将首次能够直接测量液/液界面上的电渗透流动，同时提供对输入变量的控制，这在胶体研究中是前所未有的(甚至是不可能的)。因此，这将允许对电动理论进行第一次直接和严格的测试。为了实现第二个目标，PI将开发一种低压、高压微流体泵，该泵利用新型各向异性多孔床中的横向感应电荷电动现象。学术价值：提出的微流控平台将允许在一个已有近两个世纪历史的领域进行开创性的基础研究。以前的胶体研究只能间接地探测电动流动，并且很少或根本不能控制表面电荷密度、几何形状或双层动力学。拟议的系统允许直接控制所有这些数量，并直接测量随后的流量。因此，可以研究各种物理状态：线性和非线性电动力学、瞬时双电层效应和表面电导率。将由此产生的新知识直接应用于微流控操作系统，将大大拓宽我们对诱导电荷电动力学的理解，无论是在测试不对称物体的理论方面，还是在发展集中收集的统计理论方面。在所有情况下，PI将强调最简单、最直观的系统来解释关键现象。广泛的影响：建议的电动泵可能会立即集成到现有的弹性微流体设备中，以实现快速和广泛的影响。这将使完全便携、坚固和多功能的流体操纵系统成为可能，并使手持危险传感器和医疗诊断工具以及植入式生物医学设备成为可能。PI将继续努力弥合微流控领域“应用”和“基础”社区之间的鸿沟，并设计了这一职业计划，以展示对现实世界挑战的工程解决方案的基本理解的价值，以及在设计基础研究时认真考虑现实世界挑战所能产生的影响。他将以新的美国物理学会期刊《生物微流体》编辑委员会“基础专家”的身份宣传这一观点。他将继续利用UCSB现有的、成功的项目(如加州少数族裔参与联盟)将本科生和未被充分代表的少数群体纳入他的研究，并将包括高中生和教师。教育：PI寻求重新激发学生对流体和传输现象的兴趣，方法是将微流体学作为一个令人兴奋的激励框架，强调对物理直观的理解，并解决依赖于此类现象的各种学科和应用。他将使用他关于微流体物理现象的评论文章作为多学科专题课程的基础，并作为教科书的基础。他将为非科学家/工程师开发并在网上发布一门关于微流体的新生研讨会课程，以扩大研究的影响，并更广泛地培养对微流体中出现的各种有趣、令人兴奋、令人惊讶和美丽的现象的欣赏。

AbstractCBET-0645097T. Squires, UC-Santa BarbaraMicrofabricated fluidic devices have the potential to revolutionize chemistry, biology, and medicine, much as the integrated circuit did for computing, science and technology. Sophisticated devices have already been developed to perform tasks that would be vastly more expensive, more difficult, or even impossible with macro-scale techniques. If microfluidic flows can be driven in a self-contained, portable fashion, such devices could be taken out of the lab and into the field (or under the skin). Electrokinetic flows present many advantages towards microfluidic portability; however, fundamental issues have thus far precluded their use in practical systems.This CAREER proposal describes a theoretical and experimental program with two central goals: 1) a fundamental understanding of electro-osmotic flow over liquid/liquid interfaces, and 2) the exploitation of these and related phenomena to develop truly portable microfludic manipulation systems. To achieve the first goal, the PI will develop and employ a microfluidic system that will enable, for the first time, direct measurements of electro-osmotic flow over liquid/liquid interfaces, while providing a control over the input 'variables' that is unprecedented (even impossible) in colloidal studies. As such, this will allow the first direct and stringent test of electrokinetic theories. To achieve the second goal, the PI will develop a low-voltage, high-pressure microfluidic pump that employs transverse induced-charge electrokinetic phenomena within a novel anisotropic porous bed. Intellectual Merit: The microfluidic platform proposed will allow groundbreaking, fundamental studies in a field that is nearly two centuries old. Previous colloidal studies probed electrokinetic flows only indirectly, and allowed little or no control over surface charge density, geometry, or double-layer dynamics. The proposed system allows direct control over all of these quantities, and directly measures the consequent flows. A variety of physical regimes will thus be available for study: linear and nonlinear electrokinetics, transient double-layer effects, and surface conductivity. The direct application of the resulting new knowledge to microfluidic manipulation systems will significantly broaden our understanding of induced-charge electrokinetics, both in testing theories for asymmetric bodies and in developing statistical theories for concentrated collections. In all cases, the PI will emphasize the simplest, most intuitive systems to elucidate key phenomena.Broader Impacts: The proposed electrokinetic pump may be immediately integrated intoexisting elastomeric microfluidic devices for rapid and broad impact. This will enable an entirely portable, robust, and versatile fluidic manipulation system and make possible hand-held hazard sensors and medical diagnostic tools, as well as implantable biomedical devices. The PI will continue his efforts to bridge the divide between the "application" and "fundamental" communities in microfluidics, and has designed this CAREER program to demonstrate the value of fundamental understanding in engineering solutions to real-world challenges, and the impact one can have by seriously considering real-world challenges in designing fundamental research. He will promote this view in his role as the "fundamentals expert" on the editorial board of the new American Institute of Physics journal Biomicrofluidics. He will continue to leverage existing, successful programs at UCSB (such as the California Alliance for Minority Participation) to integrate undergraduates and under-represented minorities into his research, and will include high-school students and teachers. Education: The PI seeks to re-invigorate student interest in fluid and transport phenomena by using microfluidics as an exciting motivational framework, by emphasizing physically intuitive understanding, and by addressing the variety of disciplines and applications that depend on such phenomena. He will use his review article on microfluidic physical phenomena as the basis for a multidisciplinary special-topics course and as the foundation for a textbook. He will develop and web-publish a freshman seminar course in microfluidics for non-scientists/engineers to broaden the impact of the research, and to more generally cultivate an appreciation for the variety of interesting, exciting, surprising and beautiful phenomena that occur in microfluidics.