Acoustic actuated fluorescence activated sorting of microparticles.

In this paper, we present a fluorescence activated sorter realized in a continuous flow microfluidic chip. Sorting is achieved by deflecting a focused particle stream with short acoustic bursts (2.5 ms), in a fluorescence activated configuration. The system utilizes two-dimensional acoustic pre-focusing, using a single actuation frequency, to position all particles in the same fluid velocity regime at flow rates up to 1.7 mL min(-1). Particles were sorted based on their fluorescence intensities at throughputs up to 150 particles s(-1). The highest purity reached was 80% when sorting at an average rate of 50 particles s(-1). The average recovery of a sort was 93.2 ± 2.6%. The presented system enables fluorescence activated cell sorting in a continuous flow microfluidic format that allows aseptic integration of downstream microfluidic functionalities, opening for medical and clinical applications.