Abstract

Measurement of cell compressibility by ultrasound in microfluidics

Kian-Meng Lim, Associate Professor, National University Of Singapore

Ultrasound has been used to move or manipulate micro-sized particles, such as biological cells, in microfluidic lab-on-chip systems. The phenomenon, called acoustophoresis, makes use of an acoustic radiation force that acts on the particles immersed in a sound field. This time-averaged resultant force is a second-order effect, and it arises from the scattering of the incident sound field due to differences in material properties between the particle and the surrounding medium. The direction and magnitude of the force depends on the acoustic contrast factor which is a function of the bulk moduli and densities of the particle and the surrounding medium. In this talk, the use of this acoustic radiation force to measure the bulk modulus or compressibility of cells will be presented. Numerical calculations of this radiation force on non-spherical particles will also be discussed.