Effect of therapeutic ultrasound on acoustically sensitive microcapsules.

In the area of therapeutic ultrasound activated drug delivery, difficulties exist in designing a carrier that responds to ultrasound for triggering and imaging but also provides adequate treatment potential. In this paper, we report on a novel acoustically sensitive microcapsule reservoir that can be activated with therapeutic ultrasound for payload release and can be potentially tracked using imaging. It is being designed for increased longevity and is not planned for the circulation. Here, we describe its unique formulation and demonstrate effects of therapeutic ultrasound on it at 1 MHz using a combined optical-acoustic setup on a microscope. We see membrane bulging and damage for small and large capsules with both continuous and pulsed ultrasound. We also show some preliminary work on understanding the mechanism behind these effects. The reservoirs show potential for future ultrasound activated release and imaging while being patent in form and function over several weeks.