Toward all optical lab-on-a-chip system: optical manipulation of both microfluid and microscopic particles
Toward all optical lab-on-a-chip system: optical manipulation of both microfluid and microscopic particles
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迈向全光学芯片实验室系统：微流体和微观粒子的光学操纵
DOI：
10.1117/12.560729
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发表时间：
2004
影响因子：
3
通讯作者：
Ming C. Wu
中科院分区：
文献类型：
--
作者：
P. Chiou;A. Ohta;Ming C. Wu
为了实现全光学芯片实验室系统，它需要用于微粒和微流体的光学操纵工具。光镊在操纵细胞或粒子方面引起了人们极大的兴趣。然而，它在处理微流体方面并不有效。其高的光功率要求也限制了其在高通量生物分析系统中的应用。在本文中，我们展示了两种新的机制，光电润湿（OEW）处理微滴，和光电镊子（OET）的光学操纵的微观粒子与低光功率驱动。这两种机制都依赖于光诱导的电力来进行光学操纵，而不是使用直接的光学力。光电润湿（OEW）使得能够通过光束控制液滴形式的微流体。它是基于光诱导的电润湿，这改变了表面张力的固体-液体界面在照明区域。它是通过将一层光电导材料与电润湿电极集成来实现的。通过编程照明模式，我们已经成功地演示了各种功能的液滴，如移动，分裂，合并。通过具有100 mW的光功率的光束以785 μ m/sec的速度输送100皮升的液滴。光电镊子（OET）基于光诱导介电泳（DEP）操纵细胞或颗粒。捕获或排斥微观粒子的光强度为2 W/cm ^2，比光镊所需的光强度（10^5~ 10^7 W/cm ^2）低5个数量级。含有细胞或颗粒的液体夹在光敏表面和透明ITO玻璃之间，其间有交流偏压。当激光束聚焦在光敏层上时，它在照明区域上产生虚拟电极，从而在水层处产生不均匀的电场。液体层中的细胞或颗粒被这种非均匀电场极化并被DEP力驱动。该力可以是吸引力或排斥力，这取决于粒子的介电性质和偏置频率。使用OET，我们已经证明了使用小于10 uW的光功率的聚苯乙烯颗粒和活大肠杆菌细胞的浓缩。
To achieve all-optical-lab-on-a-chip systems, it requires optical manipulation tools for both microparticles and microfluids. Optical tweezers have attracted a great deal of interests in manipulating cells or particles. However, it is not effective in handling microfluid. Its high optical power requirement also limits its application in high throughput bio-analysis system. In this paper, we demonstrate two novel mechanisms, optoelectrowetting (OEW) for handling microdroplets, and optoelectronic tweezers (OET) for optical manipulation of microscopic particles with low optical power actuation. Instead of using direct optical force, both mechanisms rely on light induced electrical force for optical manipulation. Optoelectrowetting (OEW) enables control of microfluids in droplet form by optical beams. It is based on light induced electrowetting, which changes surface tension at solid-liquid interface at illuminated area. It is realized by integrating a layer of photoconductive material with electrowetting electrodes. By programming the illumination pattern, we have successfully demonstrated various functions for droplet, such as moving, splitting, and merging. A 100 pico-liter droplet was transported at a speed of 785um/sec by an optical beam with an optical power of 100mW. Optoelectronic tweezers (OET) manipulate cells or particles based on light induced dielectrophoresis (DEP). Trapping or repelling of microscopic particles is achieved with a light intensity of 2W/cm^2, which is 5 orders of magnitudes lower than that required by optical tweezers (10^5~ 10^7 W/cm^2). The liquid containing cells or particles is sandwiched between a photosensitive surface and a transparent ITO glass, with an ac bias between them.. When the laser beam is focused on the photosensitive layer, it creates a virtual electrode on the illuminated area, resulting a non-uniform electric field at the aqueous layer. Cells or particles in the liquid layer are polarized by this non-uniform electric field and driven by the DEP force. The force could be attractive or repulsive, depending on the dielectric properties of the particles and the bias frequency. Using OET, we have demonstrated concentration of polystyrene particles and live E.coli cells using an optical power less than 10uW.