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 sono poration at 0.1 MPa of 1 or 2 MHz ultrasound. (c) 2006 Published by Elsevier Ltd.