Yao J, Obara H, Sapkota A, Takei M
Department of Mechanical Engineering, Chiba University , Chiba 263-0022, Japan.
Department of Mechanical Engineering, Tokyo Metropolitan University , Tokyo 192-0397, Japan.
Biomicrofluidics. 2016 Mar 15;10(2):024105. doi: 10.1063/1.4943859. eCollection 2016 Mar.
An optical transparent 3-D Integrated Microchannel-Electrode System (3-DIMES) has been developed to understand the particles' movement with electrokinetics in the microchannel. In this system, 40 multilayered electrodes are embedded at the 2 opposite sides along the 5 square cross-sections of the microchannel by using Micro Electro-Mechanical Systems technology in order to achieve the optical transparency at the other 2 opposite sides. The concept of the 3-DIMES is that the particles are driven by electrokinetic forces which are dielectrophoretic force, thermal buoyancy, electrothermal force, and electroosmotic force in a three-dimensional scope by selecting the excitation multilayered electrodes. As a first step to understand the particles' movement driven by electrokinetic forces in high conductive fluid (phosphate buffer saline (PBS)) with the 3-DIMES, the velocities of particles' movement with one pair of the electrodes are measured three dimensionally by Particle Image Velocimetry technique in PBS; meanwhile, low conductive fluid (deionized water) is used as a reference. Then, the particles' movement driven by the electrokinetic forces is discussed theoretically to estimate dominant forces exerting on the particles. Finally, from the theoretical estimation, the particles' movement mainly results from the dominant forces which are thermal buoyancy and electrothermal force, while the velocity vortex formed at the 2 edges of the electrodes is because of the electroosmotic force. The conclusions suggest that the 3-DIMES with PBS as high conductive fluid helps to understand the three-dimensional advantageous flow structures for cell manipulation in biomedical applications.
为了了解微通道中粒子在电动作用下的运动情况，已经开发了一种光学透明的三维集成微通道 - 电极系统（3 - DIMES）。在该系统中，通过微机电系统技术，沿着微通道的5个方形横截面在相对的两侧嵌入40个多层电极，以便在另外相对的两侧实现光学透明。3 - DIMES的概念是，通过选择激励多层电极，粒子在三维空间中由介电泳力、热浮力、电热力和电渗力等电动驱动力驱动。作为使用3 - DIMES了解高导电流体（磷酸盐缓冲盐水（PBS））中电动驱动力驱动粒子运动的第一步，通过粒子图像测速技术在PBS中三维测量一对电极作用下粒子的运动速度；同时，使用低导电流体（去离子水）作为参考。然后，从理论上讨论电动驱动力驱动的粒子运动，以估计作用在粒子上的主导力。最后，根据理论估计，粒子的运动主要由热浮力和电热力等主导力引起，而在电极两侧边缘形成的速度涡是由电渗力造成的。结论表明，以PBS作为高导电流体的3 - DIMES有助于理解生物医学应用中细胞操作的三维优势流动结构。
