Researchers from the University of California San Diego used acoustic waves to move fluids through small channels, marking the 1st time that surface acoustic waves have been used at the nanoscale. The team’s work was published this week in Advanced Functional Materials. 

The findings are an important step towards manufacturing small, portable devices for drug discovery and microbotics, according to the researchers. The devices could one day be used to sort cells move liquids, or sense other biological components for rapid diagnosis.

Moving fluids through channels that are 1,000 times smaller than the width of a hair has always challenged the field of nanofluidics. James Friend, a professor at the Jacobs School of Engineering at UC San Diego, pointed out that current methods require bulky equipment and extreme conditions, like high pressure and temperature, to manipulate fluids through channels that are only nanometers high.

Post-doctoral researcher Morteza Miansari, now at Stanford, built a device made of lithium niobate with nanoscale channels. Using acoustic waves of 20 megaHertz, researchers demonstrated that they could manipulate fluids, droplets and particles in nanoscale channels that were 50 to 250 nanometers tall. The team applied the waves in the same direction as moving fluids to fill the channels and in the opposite direction to drain the channels.

Scientists could enable the device to filter large biomolecules by changing the height of the channels. Acoustic waves would drive fluids into the channels, leaving behind the large biomolecules to form a dry mass. The research term hypothesizes that this feature could be used for rapid diagnosis in the field.