Petersson Filip, Aberg Lena, Swärd-Nilsson Ann-Margret, Laurell Thomas
Department of Electrical Measurements, Lund Institute of Technology, Lund, Sweden.
Anal Chem. 2007 Jul 15;79(14):5117-23. doi: 10.1021/ac070444e. Epub 2007 Jun 15.
A novel method, free flow acoustophoresis (FFA), capable of continuous separation of mixed particle suspensions into multiple outlet fractions is presented. Acoustic forces are utilized to separate particles based on their size and density. The method is shown to be suitable for both biological and nonbiological suspended particles. The microfluidic separation chips were fabricated using conventional microfabrication methods. Particle separation was accomplished by combining laminar flow with the axial acoustic primary radiation force in an ultrasonic standing wave field. Dissimilar suspended particles flowing through the 350-microm-wide channel were thereby laterally translated to different regions of the laminar flow profile, which was split into multiple outlets for continuous fraction collection. Using four outlets, a mixture of 2-, 5-, 8-, and 10-microm polystyrene particles was separated with between 62 and 94% of each particle size ending up in separate fractions. Using three outlets and three particle sizes (3, 7, and 10 microm) the corresponding results ranged between 76 and 96%. It was also proven possible to separate normally acoustically inseparable particle types by manipulating the density of the suspending medium with cesium chloride. The medium manipulation, in combination with FFA, was further used to enable the fractionation of red cells, platelets, and leukocytes. The results show that free flow acoustophoresis can be used to perform complex separation tasks, thereby offering an alternative to expensive and time-consuming methods currently in use.
本文提出了一种新型方法——自由流动声泳（FFA），它能够将混合颗粒悬浮液连续分离成多个出口馏分。利用声学力根据颗粒的大小和密度对其进行分离。结果表明，该方法适用于生物和非生物悬浮颗粒。微流控分离芯片采用传统微加工方法制造。颗粒分离是通过在超声驻波场中将层流与轴向声初级辐射力相结合来实现的。流经350微米宽通道的不同悬浮颗粒因此被横向平移到层流剖面的不同区域，该层流剖面被分成多个出口以进行连续馏分收集。使用四个出口，分离了2微米、5微米、8微米和10微米的聚苯乙烯颗粒混合物，每种粒径的颗粒有62%至94%最终进入单独的馏分。使用三个出口和三种粒径（3微米、7微米和10微米），相应的结果在76%至96%之间。还证明了通过用氯化铯操纵悬浮介质的密度，可以分离通常在声学上无法分离的颗粒类型。介质操纵与FFA相结合，进一步用于实现红细胞、血小板和白细胞的分级分离。结果表明，自由流动声泳可用于执行复杂的分离任务，从而为目前使用的昂贵且耗时的方法提供了一种替代方案。
