Microbubbles controlled by acoustical tweezers for highly localized drug release

Microbubbles are used every day as contrast agents in medical sonography, and are the subject of intense research for the delivery of therapeutic agents. There are a number of options available to manipulate these microbubbles, including the use of light and sound, although the potential of the latter remains largely unexplored. In their research1 published on 22 June 2020 in PNAS, CNRS researcher Diego Baresch and Valeria Garbin2 , a researcher at the Delft University of Technology (The Netherlands), show that it is entirely possible to manipulate microbubbles through the use of “acoustical tweezers,” a tool developed in 2016 that uses an acoustical beam to trap an object without contact. In using these acoustical tweezers through layers of bio-mimicking and elastic materials, they successfully surpassed the limitations of optical tweezers,3 which cannot propagate through opaque media (such as in vivo tissue). As a result, the scientists have opened the way for a broader application of acoustical tweezers in biology and biomedicine, for instance for the highly-localized, reproducible, and controlled delivery of medicine, or for in vitro tissue engineering using stem cells.

• 1This research received a post-doctoral funding from the Royal Society (Newton fellowships). This research was conducted at Imperial College London in the department of Chemical Engineering
• 2t the Institute of Mechanics and Engineering in Bordeaux (CNRS/Université de Bordeaux/Arts et Métiers Paristech/Bordeaux INP) and at TU Delft, Department of Chemical Engineering, The Netherlands.
• 3Developed by Arthur Ashkin, co-laureate of the 2018 Nobel Prize in Physics.