Theoretical exploration of shear stress generated by oscillating microbubbles on the cell membrane in the context of sonoporation

The subject of this study is shear stress exerted on the cell membrane by acoustic microstreaming generated by a contrast microbubble pulsating nearby a cell. This effect is presumed to play a major role in the sonoporation process. However, the analytical formula currently used for estimating the shear stress is based on the assumption that the bubble is hemispherical and resting on the cell membrane. Such a model is not adequate for an encapsulated bubble. In this paper, an improved theory is suggested that assumes a contrast microbubble to be detached from the cell membrane. The second problem considered is how to apply the model for pairwise bubble-cell interactions to bubble-cell solutions which one has to deal with in experiments. An approach is proposed to evaluate the number of cells undergoing sonoporation in a bubble-cell solution.