An Infrared System for Measuring Temperature Distribution in Microfluidic Devices

液滴微流控（DMF）是一种用于高通量筛选分析（HTS）的使能技术，其被许多应用所要求，诸如生命科学研究、药物发现和材料合成。DMF采用纳升大小的液滴，其可以在微通道网络中以kHz速率通过将一种流体注入另一种不混溶的流体（即水注入油中）而产生，作为用于HTS应用的移动反应器。由于它们具有小体积和三维流动，这些液滴允许快速混合，增强反应动力学，并减少试剂消耗和分析时间。使DMF能够作为HTS的实现技术的关键功能之一是加热单个液滴;许多应用，如通过聚合酶链式反应的DNA扩增，热引发聚合和点击化学，依赖于温度变化。液滴内的局部加热也可用于增强试剂的混合。 申请人目前的研究计划集中在DMF上，特别强调开发用于感测和加热单个液滴的微波技术。她的团队已经证明，微波能够在单个液滴内产生局部加热，并在15 ms内将其温度提高42度，这对扩大DMF的应用范围具有巨大的潜力，例如，用于制造聚合物珠，DNA传感，点击化学和制药工业。为了充分实现这一潜力，需要一种精确、廉价和非侵入式温度测量技术;这将通过所要求的红外（IR）成像系统实现。IR成像允许通过简单地捕获芯片的表面图像来检索微流体芯片中的液滴的温度，这对液滴是非侵入性的，易于操作，并且消除了使用温度敏感的荧光染料作为温度指示剂的需要。它的高速成像（全分辨率下每秒1000帧）与液滴传输速度相匹配，从而可以获得瞬态信息。它的高分辨率（小至3um）非常适合DMF，因为大多数液滴的长度为数十至数百微米。 这种易于操作的成像系统将允许表征DMF的微波加热，开辟了一系列新的应用，如点击化学，DNA扩增和使用加热辅助机制的传感，以及制造用于药物输送的聚合物珠。这些领域的整合使该设备将促进多学科的环境，在微流体，微波，微加工，特别是使用红外成像技术的温度测量领域的培训HQP。

Droplet microfluidics (DMF) is an enabling technology for high throughput screening analysis (HTS) demanded by many applications such as life science research, drug discovery, and material synthesis. DMF employs nanoliter-sized drops that can be generated at kHz rates in microchannel networks by injecting one fluid into another immiscible fluid (i.e. water into oil) as mobilized reactors for HTS applications. Because they have a small volume and three-dimensional flow, these droplets allow for fast mixing, enhanced reaction kinetics, and reduced reagent consumption and analysis time. One of the key functions that allow DMF to serve as an enabling technology for HTS is heating of individual droplets; many applications, such as DNA amplification via polymerase chain reaction, thermally initiated polymerization and click chemistry, rely on temperature change. Localized heating within droplets can also be utilized to enhance mixing of reagents. The applicant’s current research program focuses on DMF with a particular emphasis on developing microwave technologies for sensing and heating of individual droplets. Her team has demonstrated that microwave is capable of generating localized heating within individual droplets and increasing their temperature by 42 degrees within 15 ms, which has tremendous potential to expand the scope of applications of DMF, for example, for manufacturing polymeric beads, DNA sensing, click chemistry, and the pharmaceutical industry. To fully realize this potential requires a technique for accurate, inexpensive, and non-intrusive temperature measurement; this will be enabled by the requested Infrared (IR) Imaging system. IR imaging allows the temperature of droplets in a microfluidic chip to be retrieved by simply capturing surface images of the chip, which is non-intrusive to droplets, easy to operate, and eliminates the need to use temperature-sensitive fluorescent dyes as temperature indicators. Its high speed imaging (1000 frames per second at full resolution) matches the droplet transport speed, allowing the transient information to be obtained. Its high resolution (of as small as 3um) is well suited for DMF as most droplets have lengths of tens to hundreds of microns. This easy-to-operate imaging system will allow the characterization of microwave heating for DMF, opening up a new range of applications such as click chemistry, DNA amplification and sensing using heating-assisted mechanisms, and manufacturing polymeric beads for drug delivery. The integration of these areas enabled by this equipment will foster a multidisciplinary environment for training HQP in the field of microfluidics, microwave, microfabrication and in particular temperature measurements using IR imaging techniques.