Ultrasound-enhanced thrombolysis: Mechanistic observations
de Saint Victor M., Carugo D., Coussios C., Stride EP.
Ultrasound and microbubbles have been widely demonstrated to accelerate the breakdown of blood clots, but the mechanisms of treatment require further investigation. In particular, there is a need to clarify the effect on the fibrin matrix—the insoluble polymer mesh that determines a clot’s integrity and mechanical properties. The objective of this in vitro study was to observe in real-time the mechanisms of microbubble-enhanced sonothrombolysis at the microscale. Fluorescently labeled porcine plasma clots were prepared on a glass coverslip and exposed to different types of microbubbles with or without the fibrinolytic agent recombinant tissue plasminogen activator. A 1 mm thick piezoelectric element was coupled with the glass substrate and driven at the resonant frequency of the system (1.9 MHz), with a duty cycle of 5% and a 0.1 Hz pulse repetition frequency. The acoustic field within the clot was characterized using a fiber optic hydrophone. Changes in the fiber network were monitored for 30 min by confocal microscopy.