Yu Hongyu, Kwon Jae Wan, Kim Eun Sok
Department of Electrical Engineering, University of Southern California, 3737 Watt Way, PHE 612, Los Angeles, CA 90089-0271, USA.
Lab Chip. 2005 Mar;5(3):344-9. doi: 10.1039/b413697g. Epub 2005 Jan 24.
This paper describes a novel liquid separation technique for chembio extraction by an ultrasonic nanoliter-liquid-droplet ejector built on a PZT sheet. This technique extracts material from an aqueous two-phase system (ATPS) in a precise amount through digital control of the number of nanoliter droplets, without any mixing between the two liquids in the ATPS. The ultrasonic droplet ejector uses an acoustic streaming effect produced by an acoustic beam focused on the liquid surface, and ejects liquid droplets only from the liquid surface without disturbing most of the liquid below the surface. This unique characteristic of the focused acoustic beam is perfect (1) for separating a top-layer liquid (from the bulk of liquid) that contains particles of interest or (2) for recovering a top-layer liquid that has different phase from a bottom-layer liquid. Three kinds of liquid extraction are demonstrated with the ultrasonic droplet ejector: (1) 16 microl of top layer in Dextran-polyethylene glycol-water ATPS (aqueous two-phase system) is recovered within 20 s; (2) micron sized particles that float on water surface are ejected out with water droplets; and (3) oil layer on top of water is separated out.
本文介绍了一种基于压电陶瓷片构建的超声纳升级液滴喷射器用于化学生物提取的新型液液分离技术。该技术通过对纳升级液滴数量的数字控制，从水两相系统（ATPS）中精确提取物质，且ATPS中的两种液体之间不会发生任何混合。超声液滴喷射器利用聚焦在液体表面的声束产生的声流效应，仅从液体表面喷射液滴，而不会扰动表面以下的大部分液体。聚焦声束的这一独特特性非常适合（1）分离含有目标颗粒的顶层液体（与大量液体分离）或（2）从底层液体中回收具有不同相的顶层液体。利用超声液滴喷射器展示了三种液体提取方式：（1）在20秒内从葡聚糖 - 聚乙二醇 - 水ATPS（水两相系统）中回收16微升顶层液体；（2）漂浮在水面上的微米级颗粒随水滴被喷射出去；（3）分离出水面上的油层。
