Acoustical tweezers trap microbubbles

Amazing stuff! This is admittedly an older science related article from July 2020!

"... that the acoustic version [as opposed to optical tweezers] employs a helicoidal or “vortex” beam of ultrasound. This, he says, has several benefits for medical applications. ... Ultrasound can also penetrate deeper into opaque media such as biological tissue than optical waves ..."

"Remote positioning and activation of drug-loaded microparticles in vivo are a central pursuit of nanomedicine. Optical, magnetic, and acoustic fields have been used to position and sort microparticles in vitro, but the translation in vivo remains challenging. ... acoustical tweezers are considered an ideal candidate for in vivo contactless manipulation. ...Here we use a single-beam acoustical trap to manipulate microbubbles in three dimensions through materials that mimic biological tissues. We establish the trapping mechanism, which is strikingly different from conventional acoustic trapping of bubbles. We also demonstrate controlled release from nanoparticle-loaded microbubbles with an independent acoustic trigger. ..."

Acoustical tweezers trap microbubbles – Physics World Researchers at Imperial College London, UK have demonstrated for the first time that microscopic bubbles of gas can be manipulated using sound waves. The new “acoustical tweezers” overcome certain limitations of their optical cousins (such as not propagating well through opaque tissues), and could therefore enable a host of biomedical applications.

Here is the link to the underlying research paper:

Acoustic trapping of microbubbles in complex environments and controlled payload release