January 25, 2017
The new acoustic whirlpool device with a penny for scale. The acoustic transducer creates a whirlpool in the long, thing, blue capillary tube that effectively concentrates nanoparticles. Credit: Duke University
Mechanical engineers at Duke University have demonstrated a tiny whirlpool that can concentrate nanoparticles using nothing but sound. The innovation could gather proteins and other biological structures from blood, urine or saliva samples for future diagnostic devices.
Early diagnosis is key to successfully treating many diseases, but spotting early indicators of a problem is often challenging. To pick out the first warning signs, physicians usually must concentrate scarce proteins, antibodies or other biomarkers from small samples of a patient's body fluid to provide enough of a signal for detection.
While there are many ways to accomplish this today, most are expensive, time-consuming or too cumbersome to take to the field, and they might require trained experts. Duke engineers are moving to develop a new device that addresses these obstacles.
In a new study, researchers paired a small acoustic transducer to a glass cylinder to produce a whirlpool that can capture these disease-signaling nanoparticles in its vortex. The system shows early promise for new diagnostic devices because it is compact, inexpensive, low-energy and does not alter the properties of the corralled particles.
The results appear online on January 25, 2017, in the journal American Chemical Society Nano.
A sample of 500 nanometer particles in solution. In the top image, the acoustic whirlpool device turned off. The bottom image shows that when the device is turned on, the nanoparticles are concentrated to the point of becoming visible as a …more
"Diagnosis impacts about 70 percent of healthcare decisions," said Tony Huang, professor of mechanical engineering and materials science at Duke. "If we can improve the quality of diagnostics while reducing its costs, then we can tremendously improve the entire healthcare system."
The new technology relies on calculating and manipulating the effects of the two forces associated with sound waves—acoustic radiation and acoustic streaming. If you've ever blown air across the top of a bottle to create a tone, then you're familiar with the latter. Acoustic streaming is the same phenomenon but in reverse, where a vibrating body induces a fluid to flow.