Using feedback control of microflows to independently steer multiple particles
Using feedback control of microflows to independently steer multiple particles
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DOI：
10.1109/jmems.2006.878863
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发表时间：
2006-08-01
影响因子：
2.7
通讯作者：
Shapiro, Benjamin
中科院分区：
文献类型：
--
作者：
Armani, Michael D.;Chaudhary, Satej V.;Shapiro, Benjamin
在本文中，我们展示了如何将联合收割机和反馈控制相结合，以在两个空间维度上以微米精度独立地操纵多个粒子。通过创建一个流体流来引导粒子，该流体流将所有粒子从它们所在的位置带到它们在每个时间步长应该在的位置。我们的控制回路包括传感，计算和驱动，以引导粒子沿着用户输入的轨迹。颗粒位置由光学系统实时识别，并传输到控制算法，然后控制算法确定创建流场所需的电极电压，以将所有颗粒携带到它们的下一个期望位置。该过程在下一时刻重复。我们的方法通过在微流体通道中使用传统的电渗致动来实现廉价的颗粒转向。这种类型的粒子转向不需要光学陷阱，并且可以非侵入性地转向中性或带电粒子以及无法被激光镊子捕获的物体。（激光镊子不能操纵反射粒子，或者折射率低于周围介质的折射率的粒子（或者对于更复杂的光学涡旋全息镊子来说，与周围介质的折射率没有实质性差异）。我们展示了具有四个和八个电极的概念验证PDMS设备，其控制算法可以分别控制一个和三个粒子。特别是，我们通过实验证明，可以使用电渗流来准确地引导和捕获多个粒子。
In this paper, we show how to combine microfluidics and feedback control to independently steer multiple particles with micrometer accuracy in two spatial dimensions. The particles are steered by creating a fluid flow that carries all the particles from where they are to where they should be at each time step. Our control loop comprises sensing, computation, and actuation to steer particles along user-input trajectories. Particle locations are identified in real-time by an optical system and transferred to a control algorithm that then determines the electrode voltages necessary to create a flow field to carry all the particles to their next desired locations. The process repeats at the next time instant. Our method achieves inexpensive steering of particles by using conventional electroosmotic actuation in microfluidic channels. This type of particle steering does not require optical traps and can noninvasively steer neutral or charged particles and objects that cannot be captured by laser tweezers. (Laser tweezers cannot steer reflective particles, or particles where the index of refraction is lower than (or for more sophisticated optical vortex holographic tweezers does not differ substantially from) that of the surrounding medium.) We show proof-of-concept PDMS devices, having four and eight electrodes, with control algorithms that can steer one and three particles, respectively. In particular, we demonstrate experimentally that it is possible to use electroosmotic flow to accurately steer and trap multiple particles at once.