Sonothrombolysis with magnetically targeted microbubbles

Journal article

Microbubble-enhanced sonothrombolysis is a promising approach to increase the safety and efficacy of current pharmacological treatments for ischemic stroke. Maintaining therapeutic concentrations of microbubbles and drugs at the clot site however poses a challenge. The objective of this study was to investigate the efficacy of magnetic microbubble targeting upon clot lysis rates in vitro. Retracted whole porcine blood clots were placed in a flow phantom of a partially occluded middle cerebral artery. The clots were treated with a combination of tissue plasminogen activator (0.75µg/mL), magnetic microbubbles (~107 microbubbles/mL), and ultrasound (0.5MHz, 630kPa peak rarefactional pressure, 0.2Hz pulse repetition frequency, 2% duty cycle). Magnetic targeting was achieved using a single permanent magnet element (0.08-0.38T and 12-140T/m in the region of the clot). The change in clot diameter was measured optically over the course of the experiment. Magnetic targeting produced a three-fold average increase in lysis rates and linear correlation was observed between lysis rate and total energy of acoustic emissions.

Authors: de Saint Victor, M; Barnsley, L; Carugo, D; Owen, J; Coussios, C

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Elsevier
• Journal: Ultrasound in Medicine and Biology
• Volume: 45
• Issue: 5
• Pages: 1151-1163
• Publication date: 2019-02-14
• Acceptance date: 2018-12-22
• DOI: 10.1016/j.ultrasmedbio.2018.12.014
• EISSN: 1879-291X
• ISSN: 0301-5629
• Keywords: thrombolysis; microbubbles; clot; drug delivery; ultrasound; passive cavitation detection; magnetic targeting