Optical/Thermal Droplet Levitation and Transport for Lab-On-A-Chip

这项研究旨在将通过以前的联邦支持获得的知识应用于芯片实验室处理（Bousse, et al. 2000, Whitesides &; Stroock 2001）。这些小型化的微流体装置从一个点到另一个点运输微量液体样品和试剂，用于测试目的。通常，这种微流体装置由一系列微机械通道或毛细血管组成，液体以各种方式通过这些通道或毛细血管（Stone, et al. 2004）。在许多“泵送”策略中，在孤立液滴的两端之间产生很大的压差，以简单地推动液滴通过毛细管，与毛细管半径的四次方成反比。这项工作的智力优势集中在开发和使用一种新的光学/热策略，用于液滴传输和混合，使用“永久不润湿”，使用热毛细对流来防止液体样品接触固体表面，尽管它们非常接近。这些悬浮的液滴以非常低的摩擦在固体表面上移动，使液体在很少的力的情况下从一点移动到另一点，并在更短的时间内提高了设备的吞吐量。通过将液滴封装在不混相油中，将促进液滴的运输（对生物芯片应用最感兴趣）。由热毛细作用驱动的强烈的内部对流促进了被封装样品的合并以及内容物的混合，否则大多数低雷诺数方案都是困难的。所提出的封装液滴传输机制也将抑制样品到样品的污染。这项研究的广泛影响包括对医疗器械行业的好处等。作为这项研究的一部分，我们与迪卡尔布县教育委员会下属的芬班克科学中心（Fernbank Science Center）建立了伙伴关系，共同开发一系列实验，以激发中学生对液滴动力学和流体物理学的兴趣。这些实验不仅仅是简单的演示，而是要求学生收集和分析数据作为练习的一部分。PI将努力推动这项令人兴奋的研究，并通过给亚特兰大大学中心（莫尔豪斯与斯派曼学院、克拉克-亚特兰大大学）的本科生讲课，鼓励少数族裔学生考虑攻读工程学研究生。

CBET-0828820NeitzelThis research seeks to apply knowledge gained through previous federal support to lab-on-a-chip processing (Bousse, et al. 2000, Whitesides & Stroock 2001). These miniaturized microfluidics devices transport minute liquid samples and reagents from point to point for testing purposes. Typically, such a microfluidics device consists of an array of micro-machined channels or capillaries through which the liquids are forced in a variety of fashions (Stone, et al. 2004). In many 'pumping' strategies, a large pressure difference is created between the ends of an isolated droplet to simply push the droplet through the capillary inversely proportional the capillary radius to the fourth power. The intellectual merits of this work centers on developing and using a novel optical/thermal strategy for droplet transport and mixing using 'permanent nonwetting', using thermocapillary convection to keep liquid samples from contacting solid surfaces, although they are in close proximity. These levitated droplets translate above a solid surface with very low friction, enabling the movement of liquid from point to point with little force, and in shorter time, improving device throughput. Transport of aqueous droplets (of greatest interest for bio-chip applications) will be facilitated by encapsulating the aqueous droplet within immiscible oil. The vigorous internal convection driven by thermocapillarity promotes merging of encapsulated samples as well as mixing of the contents, otherwise difficult with most low-Reynolds-number schemes. The proposed encapsulated-droplet-transport mechanism will also inhibit sample-to-sample contamination. The broader impacts of this research include benefits to the medical-device industry, among others. As part of this research, a partnership has been established with the Fernbank Science Center, a division of the Dekalb County (GA) Board of Education, to develop an ensemble of experiments to stimulate interest in droplet dynamics and fluid physics in secondary school students. These experiments, more than simple demonstrations, require students to collect and analyze data as part of the exercise. The PI will endeavor to promote this exciting research and stimulate minority students to consider graduate study in engineering by giving lectures to undergraduate students in schools of the Atlanta University Center (Morehouse & Spellman Colleges; Clark-Atlanta University).