Imagine a cell with specially equipped potent balloons that pop when placed near an ultrasound beam—killing surrounding cancer cells in its wake.
Key to this operation are tiny protein bubbles called gas vesicles. If a microbe wishes to rise to the surface, it can generate a few gas vesicles, making its body more buoyant and pushing it upwards. If it wishes to sink, it can pop a few gas vesicles and do the opposite.
Scientists have been able to genetically engineer microbes that can go into the body, where they’re detectable by an ultrasound machine. When a gas vesicle pops, the gas inside fizzes away. But, by driving that gas with finely tuned ultrasound waves, researchers learned they could force gas bubbles to grow, and grow—until the bubbles themselves also pop, violently, creating shockwaves.
Scientists call that process inertial cavitation, and it’s the same science that makes it possible for ultrasound to clean your jewellery.
The study’s authors posed the question – could these shockwaves, generated from ultrasound-inflated bubbles, be used to work against tumours?
If a cell could be genetically engineered to produce gas vesicles, then it could be turned into a potent sleeper agent—ready to be activated by ultrasound. Researchers placed gas vesicles into a petri dish, along with a type of glioblastoma cells and found that after they blasted the dish with ultrasound, in a matter of mere seconds, they saw signs of widespread disruption that indicated the gas vesicles were responsible.