Taylor Jay K, Ren Carolyn L, Stubley G D
Dept. of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON, Canada N2L 3G1.
Biotechnol Prog. 2008 Jul-Aug;24(4):981-91. doi: 10.1002/btpr.7.
The development of lab-on-a-chip devices calls for the isolation or separation of specific bioparticles or cells. The design of a miniaturized cell-sorting device for handheld operation must follow the strict parameters associated with lab-on-a-chip technology. The limitations include applied voltage, high efficiency of cell-separation, reliability, size, flow control, and cost, among others. Currently used designs have achieved successful levels of cell isolation; however, further improvements in the microfluidic chip design are important to incorporate into larger systems. This study evaluates specific design modifications that contribute to the reduction of required applied potential aiming for developing portable devices, improved operation reliability by minimizing induced pressure disturbance when electrokinetic pumping is employed, and improved flow control by incorporating directing streams achieving dynamic sorting and counting. The chip designs fabricated in glass and polymeric materials include asymmetric channel widths for sample focusing, nonuniform channel depth for minimizing induced pressure disturbance, directing streams to assist particle flow control, and online filters for reducing channel blockage. Fluorescence-based visualization experimental results of electrokinetic focusing, flow field phenomena, and dynamic sorting demonstrate the advantages of the chip design. Numerical simulations in COMSOL are validated by the experimental data and used to investigate the effects of channel geometry and fluid properties on the flow field.
芯片实验室设备的发展需要对特定的生物颗粒或细胞进行分离。用于手持操作的小型细胞分选设备的设计必须遵循与芯片实验室技术相关的严格参数。这些限制包括施加电压、细胞分离效率高、可靠性、尺寸、流量控制和成本等。目前使用的设计已经实现了一定程度的细胞分离成功；然而，微流控芯片设计的进一步改进对于融入更大的系统很重要。本研究评估了特定的设计修改，这些修改有助于降低所需的施加电势，旨在开发便携式设备；通过在采用电动泵时最小化感应压力干扰来提高操作可靠性；通过合并导向流来实现动态分选和计数，从而改善流量控制。用玻璃和聚合物材料制造的芯片设计包括用于样品聚焦的不对称通道宽度、用于最小化感应压力干扰的不均匀通道深度、用于辅助颗粒流控制的导向流以及用于减少通道堵塞的在线过滤器。基于荧光的电动聚焦、流场现象和动态分选的可视化实验结果证明了芯片设计的优势。COMSOL中的数值模拟通过实验数据进行了验证，并用于研究通道几何形状和流体特性对流场的影响。
