Researchers from Nanyang Technological University in Singapore developed a 3D-printed device that harnesses high-pressure ultrasound to move, manipulate or destroy tiny objects. By controlling these photo-acoustic waves, the device could be useful for performing precise surgery, according to a study published in Applied Physics Letters.
“The advantage of acoustics is that it’s noninvasive,” principal investigator Claus-Dieter Ohl said in prepared remarks. “We have much better control of the photo-acoustic wave, and the wave can be even designed such that it serves the purpose of a mechanical actuator.”
Other devices produce a kind of acoustic wave known as a planar wave, which focuses to a single point. These devices are called laser-generated focused ultrasound transducers, and they covert laser pulses into vibrations.
A laser pulse hits the glass surface of the device, which is coated in carbon nanotubes. The heat causes the coating to expand, generating vibrations that produce high-frequency and high-pressure acoustic waves.
Instead of using glass, the team of researchers used 3D printers to make a lens from a clear liquid resin. Because the 3D printer can make a lens of any shape, the team could generate acoustic waves of any shape. This allows the researchers to focus the waves at multiple points simultaneously or to control the phase of the waves.
Their transducer generated a planar and focused wave at the same time, performing just as well as a traditional glass one. The 3D-printed device costs about $2 to print, according to the team, and it can focus down to hundreds of microns.
Ohl suggested that the device could assist eye surgeons while they’re conducting cataract surgery. The team also pointed out that biomedical researchers could use the acoustic waves to measure elastic properties of cells in a petri dish to see how they respond to forces.
