Acoustofluidics With High Selectivity Using Spatio-Temporal Modulated Saws

Surface acoustic waves (SAWs) based microfluidics show promising applications in bio-particle processing due to the attributes of simple fabrication and high efficiency. However, most of the SAWs based microfluidics are designed to deal with massive targets, unable to discriminate the same micro-particles in space. The improvement of spacial selectivity is demanded to extend the application of this technology, especially in bioengineering. In this paper, we propose a hybrid method, combining the spacial and temporal modulation of incident waves to build acoustofluidics with two-dimensional high selectivity. A simplified 2D finite-element model is adopted to predict the device performance and the numerical analysis gives a clearly explanation of the working principle. The experimental results with 7um polystyrene particles validate the anticipated high selectivity. And the proposed device even has the potential to achieve single particle manipulation.