The non-thermal influences of ultrasound on cell membrane: A molecular dynamics study.

Numerous experimental studies have shown that the interaction of ultrasound with different cell membranes can result in a wide range of non-thermal effects on different cells or their membrane, including increased membrane permeability, ultrasonic cavitation in cells, and increased gene and drug delivery. However, the molecular mechanism for the interaction between ultrasound and cell membrane remains unclear. In this study, we model ultrasonic waves as cycles of alternating positive and negative pressure, and then use atomic molecular dynamics simulation to investigate how the applied ultrasound affects the structure of cell membranes and the corresponding molecular distribution of dissolved gas. We find that ultrasound energy is concentrated more effectively on the hydrophobic core of the membrane because it causes a strong oscillation of membrane thickness while producing a much weaker response in the surrounding water. In addition, our simulations reveal a substantial effect of the ultrasonic frequency on redistribution of dissolved gas molecules, and only an ultrasound with a long period can result in a significant gas redistribution. [ABSTRACT FROM AUTHOR]