Tkaczyk Alan H, Tkaczyk Eric R, Norris Theodore B, Takayama Shuichi
Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Blvd., Ann Arbor, MI 48109-2099, USA.
Department of Mechanical Engineering, University of Michigan, 2350 Hayward St., Ann Arbor, MI 48109-2125, USA.
J Mech Med Biol. 2011 Mar;11(1):1-14. doi: 10.1142/S0219519410003617.
Microfluidic droplets formed in emulsions are used in a variety of analytical techniques and hold great potential for future scientific and commercial applications. Our experiments merge quantitative quality engineering methods into the microdroplet field. We present a unique microdroplet generation and consistency monitoring system with laser optics excitation and detection. Our setup analyzes each droplet with sub-millisecond signal resolution and single photon accuracy, and is compatible with process control methods. To demonstrate the consistency of microdroplet generation over time, we measure and examine the mean frequency of aqueous plug-shaped droplet (microplug) formation in oil phase, as well as the mean length of plugs, and the interval between consecutive droplets. We also demonstrate the detection of cancer cells encapsulated within aqueous microdroplets in continuous oil phase flow. Two-channel optical monitoring allows for the simultaneous and independent inspection of both microdroplet generation and identification of green fluorescent protein-labelled cancer cells within the droplets. Increased accuracy and consistency are central to many established and developing microfluidic technologies. A systematic, quantitative approach as demonstrated with our experiments may be essential in the development of advanced microfluidic concepts that require exacting reproducibility and would greatly benefit from incorporated automated measurement techniques for process control.
乳液中形成的微流控液滴被用于各种分析技术，在未来的科学和商业应用中具有巨大潜力。我们的实验将定量质量工程方法融入微滴领域。我们展示了一种独特的微滴生成和一致性监测系统，该系统采用激光光学激发和检测。我们的装置以亚毫秒级信号分辨率和单光子精度分析每个液滴，并且与过程控制方法兼容。为了证明微滴生成随时间的一致性，我们测量并检查了油相中水相塞状液滴（微塞）形成的平均频率、微塞的平均长度以及连续液滴之间的间隔。我们还展示了在连续油相流中对包裹在水相微滴内的癌细胞的检测。双通道光学监测允许同时且独立地检查微滴生成以及液滴内绿色荧光蛋白标记癌细胞的识别。提高准确性和一致性是许多成熟和正在发展的微流控技术的核心。正如我们的实验所展示的，一种系统的定量方法对于开发需要严格可重复性的先进微流控概念可能至关重要，并且将极大地受益于用于过程控制的集成自动化测量技术。
