Controlling Fluids with Acoustic Waves at the Nanoscale

Discovery in nanofluidics could lead to medical breakthroughs.

The use of acoustic waves to manipulate fluids through channels at the nanoscale level represents a long-sought breakthrough in the field of nanofluidics. Researchers have struggled to move fluids at such a small scale due to the traditionally required use of high temperatures, expensive equipment and pressures of 1 megaPascal (the equivalent of 10 atmospheres).

A team of mechanical engineers at the University of California San Diego, led by James Friend, has been attempting to utilize acoustic waves to move fluids for many years, but it was the development of a device containing nanoscale channels and constructed from lithium niobate which spurred new life into the nanofluidics field.

The new technique involves the use of acoustic waves (with a frequency of 20 megaHertz) to move fluids in nanoslits measuring from 50 to 250 nanometers in height. By altering the direction of the acoustic waves relative to the fluid and the height of the channels, the researchers were able to separate particles from their original fluidic form and isolate them in the shape of a dry mass.

The key advantage stemming from this new device is its ability to move fluids at room temperature, allowing for significant reductions in cost and complexity of the entire process.

The implications of this discovery range from the ability to sort, isolate and analyze individual cells and other biological elements, to a new method of filtering particles and bacteria. On the whole, this technique has the potential to greatly enhance the speed and efficiency of medical diagnostic methods.

For a very different application of acoustic waves, learn how engineers create acoustic holograms.