Can we harness cavitation for therapeutic benefit?

Abstract

Therapeutic ultrasound and cavitation nucleation agents are currently being developed for a range of clinical applications such as enhanced cardiovascular drug delivery, blood brain barrier disruption, immunotherapy, sonothrombolysis, sonobactericide, and bioactive gas delivery. Microbubbles oscillate when exposed to ultrasound and create stresses directly on nearby tissue that elicit a biological response, thereby enhancing drug transport into vascular tissue, biofilm, thrombi, or tumors. Catheter-directed therapeutics in combination with an ultrasound contrast agent nucleate sustained bubble activity and enhanced drug penetration and efficacy. Passive cavitation imaging aids in mapping the spatial and temporal extent as well as type of bubble activity. The conditions for the onset of inertial and stable cavitation will be reviewed in the context of the Mechanical and Cavitation Indices. Successful implementation of ultrasound and cavitation nuclei-mediated drug and bioactive gas delivery has the potential to change the way drugs are administered systemically, resulting in more effective therapeutics and less-invasive treatments.