Parallel trapping, patterning, separating and rotating of micro-objects with various sizes and shapes using acoustic microstreaming

Parallel multifunctional methods for cell micromanipulation are invaluable tools in biomedicine, bioengineering, and biophysics. However, one of the key limitations of the most existing lab-on-chip devices is the challenge to integrate multiple operations into single microchip. A novel noncontact acoustic micromanipulation method based on acoustic microstreaming, capable of trapping, patterning, separating, and rotating micro-objects with various sizes and shapes, is proposed. Herein, two types of highly-localized microvortices, referred to as “inner microvortex” and “outer microvortex”, are generated by an acoustic vibration applied to custom-designed microcavity array bottoms, and utilized to achieve parallel multifunctional micromanipulation. Experiments of microbeads are conducted to verify the proposed functions and quantify the key parameters that influence the acoustofluidic device performance. Subsequently, further multifunctional micromanipulation of living cells, including trapping and isolating circulating tumor cells with the capturing efficiency of more than 90 %, or tunable trapping and rotating of swine oocytes, is demonstrated, to show the manipulated forces can be effectively tuned on demand for different cell studies. Finally, another important application in multifunctional operation of motile micro-organisms (that is, Euglena gracilis) in a noninvasive manner (viability: 100 %) is shown. Our AMM technique is easy, robust, biocompatible, and becomes a potential valuable tool in biological micromanipulation.