Determination of microbubble cavitation threshold pressure as function of shell chemistry

Abstract

The sensitivity of inertial cavitation threshold to changes in shell viscosity and elasticity makes shell chemistry (here, polyethylene glycol (PEG) molecular weight and composition) a potential tuning parameter for microbubble based ultrasound contrast and drug delivery applications. It is anticipated that microbubble shell chemistry can be used to adjust the inertial cavitation threshold so as to either avoid or achieve cavitation at a given operating pressure. Here such ideas are tested by measuring the inertial cavitation threshold for populations of phospholipid shelled microbubbles suspended in aqueous media, and this method is used to quantify the influence of shell chemistry on the inertial cavitation threshold. The experimental cavitation data are fitted with a modification of the Herring equation, using shell viscosity and elasticity as the tuning parameters. It is concluded that the design and synthesis of microbubbles with a prescribed inertial cavitation threshold is feasible using PEG molecular weight and composition as tuning parameters. © 2010 Maney Publishing.