Shear stress in cells generated by ultrasound

An experimental study using a mason horn of 21.4 kHz indicated that the threshold shear stress for cell sonoporation was 12±4 Pa for ultrasound exposure time up to 7 min. Numerical calculations have shown that shear stress associated with microstreaming surrounding encapsulated bubbles may be large enough to generate sonoporation at 0.1 MPa of 1 or 2 MHz ultrasound.