Synthesized-sound manipulation of microparticles: Principle and experiments

Arranging microparticles into desired pattern is of particular importance for many applications in the field of micro-electronics-mechanical system, regenerative medicine, tissue engineering and composite fabricating. A variety of techniques for patterning microparticles on the substrate have been developed in recent years based on optic, magnetic and electric field. However, each above mentioned techniques have their own potential drawbacks. The noninvasive property and little limitation of manipulating target make acoustic-based microparticle-patterning a promising alternative to the above mentioned methods. But in existing manipulations, the pattern shapes are limited and thus may hind the possible applications. In this work, we propose a method to create diverse programmable microparticle-patterns within an ultrasonic chamber. Multi-transducer based sound field synthesis technique, including mode matching and inverse filter, has been employed to design and built the trapping sound field corresponding to the desired microparticle-patterns.