Modulation of fluidic resistance and capacitance for long-term, high-speed feedback control of a microfluidic interface
Modulation of fluidic resistance and capacitance for long-term, high-speed feedback control of a microfluidic interface
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DOI：
10.1039/b822423d
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发表时间：
2009-01-01
期刊：
影响因子：
6.1
通讯作者：
Messner, William C.
中科院分区：
文献类型：
--
作者：
Kim, YongTae;Kuczenski, Brandon;Messner, William C.
现有的微流体系统可以通过引导层流之间的界面来控制局部化学环境，用于从亚细胞刺激到燃料电池的应用。然而，传统的流量调节方法尚未提供鲁棒且可靠的方式来动态地控制层流界面很长时间。这种控制在生物学研究中很重要，因为活细胞和组织的响应时间可能长达几天。在这里，我们描述了一种新的长期的，高速的方法，采用调制的流体储液器和微流体网络之间的流体阻力和流体电容与反馈控制，使长期的动态控制的微流体接口的时间和空间。我们的方法涉及通过捏方法来收缩窄管以调节流体阻力，同时还通过挤压方法来控制流体网络中的小可变储集器以调节流体电容。我们设计了一个良好的调整比例-积分-微分（PID）控制器的闭环控制系统，导致短期（2秒）和长期（15小时）实验的压力控制。此外，我们将基于压力的反馈控制方法集成到这种方法中，这使得我们的微流体界面能够在大于1 Hz的频率下进行长期时空控制，并且水库容量能够使实验持续超过60天。这种长期和高速的控制是不可能的标准微流体实验室实践。我们的系统具有多种潜在应用，包括癌症转移或胚胎发育的长期细胞研究。
Existing microfluidic systems can control local chemical environments by directing the interface between laminar flowing streams for applications ranging from subcellular stimulation to fuel cells. However, conventional flow modulation methods have not yet provided a robust and reliable way to dynamically control laminar flow interfaces for very long time periods. Such control is important in biological investigations, since response times for living cells and tissues can be as long as several days. Here, we describe a novel long-term, high-speed approach that employs modulation of fluidic resistance and fluidic capacitance between a fluid reservoir and a microfluidic network with feedback control to enable long-term dynamic control of a microfluidic interface in time and space. Our method involves constricting a narrow tube through a pinching approach to modulate fluidic resistance while also controlling a small variable reservoir in the fluidic network through a squeezing approach to modulate fluidic capacitance. We designed a well-tuned proportional-integral-derivative (PID) controller for the closed-loop control system that resulted in control of pressure for short-term (2 s) and long-term (15 h) experiments. Further, we integrated a pressure-based feedback control approach into this method, which enables both long-term spatiotemporal control of our microfluidic interface at frequencies greater than 1 Hz and a reservoir capacity to enable experiments for longer than 60 days. This long-term and high-speed control is not possible with standard microfluidic laboratory practices. Our system has a diversity of potential applications including long-term cellular studies in cancer metastasis or embryonic development.