As they began researching the combination of mechanophores and ultrasound, they discovered a problem: Ultrasound could activate the mechanophores, but only at an intensity so strong that it also damaged neighboring tissues. What the researchers needed was a way to focus the energy of the ultrasound right where they wanted it. It turned out that Shapiro’s gas vesicle technology provided the solution.
In his previous work, Shapiro made use of the vesicles’ tendency to vibrate or “ring” like a bell when bombarded with ultrasound waves. In the current research, however, the vesicles are rung so hard that they break, which focuses the ultrasound energy. The vesicles effectively become tiny bombs whose explosions activate the mechanophore.