Shah Gaurav J, Kim Chang-Jin Cj
UCLA, 420 Westwood Plaza, Engineering IV Bldg, Los Angeles, CA, USA90095, USA.
Lab Chip. 2009 Aug 21;9(16):2402-5. doi: 10.1039/b823541d. Epub 2009 May 27.
Due to the lack of continuous flows that would wash unwanted specifies and impurities off from a target location, droplet microfluidics commonly employs a long serial dilution process to purify target species. In this work, we achieve high-purity separation for the case of electrowetting-on-dielectric (EWOD) based droplet microfluidics by introducing a "fluidic conduit" between a sample droplet and a buffer droplet. The long and slender fluidic path minimizes the diffusion and fluidic mixing between the two droplets (thus eliminating non-specific transport) but provides a conduit between them for actively transported particles (thus allowing the specific transport). The conduit is purely fluidic, stabilized chemically (e.g. using surfactants) and controlled by EWOD. The effectiveness of the technique is demonstrated by eliminating approximately 97% non-magnetic beads in just one purification step, while maintaining high collection efficiency (>99%) of magnetic beads.
由于缺乏能够将不需要的特定物质和杂质从目标位置冲洗掉的连续流，液滴微流控技术通常采用长时间的连续稀释过程来纯化目标物质。在这项工作中，我们通过在样品液滴和缓冲液滴之间引入一个“流体管道”，实现了基于介电电泳（EWOD）的液滴微流控技术的高纯度分离。细长的流体路径使两个液滴之间的扩散和流体混合最小化（从而消除非特异性传输），但为主动传输的颗粒在它们之间提供了一个管道（从而允许特异性传输）。该管道纯粹是流体的，通过化学方法（例如使用表面活性剂）稳定，并由EWOD控制。通过在仅仅一个纯化步骤中消除约97%的非磁性珠子，同时保持磁性珠子的高收集效率（>99%），证明了该技术的有效性。
