Technique transports nonmagnetic particles such as cells, water droplets and coffee grounds
Courtesy of Dimos Poulikakos
Levitating objects can spin, glide and collide together — no magnets or magic tricks required.
Using steady streams of sound waves, engineers maneuvered hovering toothpicks, coffee granules and water droplets through the air, a team from ETH Zurich reports July 15 in the Proceedings of the National Academy of Sciences. Scientists could use the touch-free technique to gently handle delicate or hazardous lab chemicals or to avoid contaminating cells in biological experiments.
“It’s a beautiful piece of work,” says Penn State bioengineer Tony Jun Huang, who has used sound to manipulate particles in liquid. In a single device, the study’s authors can move two airborne particles in different directions or make them converge. No one has done that before, Huang says.
Scientists have known for years how to use sound waves to hoist particles in the air, a process known as acoustic levitation. But moving the lifted bits around was more