Pulsating Tandem Microbubble for Localized and Directional Single-Cell Membrane Poration

Abstract

The interaction of laser-generated tandem microbubble (maximum diameter of about 50 mu m) with single (rat mammary carcinoma) cells is investigated in a 25-mu m liquid layer. Antiphase and coupled oscillation of the tandem microbubble leads to the formation of alternating, directional microjets (with max microstreaming velocity of 10 m/s) and vortices (max vorticity of 350 000 s(-1)) in opposite directions. Localized and directional membrane poration (200 nm to 2 mu m in pore size) can be produced by the tandem microbubble in an orientation and proximity-dependent manner, which is absent from a single oscillating microbubble of comparable size and at the same stand-off distance.