The acoustic radiation force of a focused ultrasound beam on a suspended eukaryotic cell

Although ultrasound tools for manipulating and permeabilizing suspended cells have been available for nearly a century, accurate prediction of the distribution of acoustic radiation force (ARF) continues to be a challenge. We therefore developed an analytical model of the acoustic radiation force (ARF) generated by a focused Gaussian ultrasound beam incident on a eukaryotic cell immersed in an ideal fluid. The model had three layers corresponding to the nucleus, cytoplasm, and membrane, of a eukaryotic cell. We derived an exact expression for the ARF in relation to the geometrical and acoustic parameters of the model cell components. The mechanics of the cell membrane and nucleus, the relative width of the Gaussian beam, the size, position and aspect ratio of the cell had significant influence on the ARF. The model provides a theoretical basis for improved acoustic control of cell trapping, cell sorting, cell assembly, and drug delivery.