Fundamentals and applications of acoustics in microfluidics

Acoustics is a research field covering a wide range of systems with distinct capabilities and functionalities depending on the properties and scales of acoustic waves. Acoustics applied in microfluidics has spawned new technologies and novel applications. Considering the simplicity and versatility, acoustic systems carry important advantages and potential to manipulate matter within the domains of miniaturization, point-of-care diagnostics, and lab-on-a-chip applications compared to the optic, magnetic, electric, thermal, and hydrodynamic-based approaches. The main features of acoustic systems are biocompatibility, applicable sample sizes, and types, and varying modes of manipulations. With these features, acoustic systems enable single cell studies, cell sorting and separation, modal animal manipulation, nanoparticle patterning and separation, and liquid sample handling. In this chapter, fundamental physics, technical basics, and some of the applications of acoustics systems in microfluidics will be discussed.