Sound waves to help develop 'lab on a chip' device

The device uses two beams of sound-waves to act as acoustic tweezers and sort a continuous flow of cells on a dime-sized chip, said Tony Jun Huang, associate professor of engineering science and mechanics.

By changing the frequency of the acoustic waves, researchers can easily alter the paths of the cells.

Huang said that since the device can sort cells into five or more channels, it will allow more cell types to be analysed simultaneously, which paves the way for smaller, more efficient and less expensive analytic devices.

"Eventually, you could do analysis on a device about the size of a cell phone. It's very doable and we're making in-roads to that right now," said Huang.

Biological, genetic and medical labs could use the device for various types of analysis, including blood and genetic testing, Huang said.

Most current cell-sorting devices allow the cells to be sorted into only two channels in one step, according to Huang, adding another drawback of current cell-sorting devices is that cells must be encapsulated into droplets, which complicates further analysis.

"Today, cell sorting is done on bulky and very expensive devices. We want to minimize them so they are portable, inexpensive and can be powered by batteries," said Huang.

Using sound waves for cell sorting is less likely to damage cells than current techniques, Huang added.

Researchers created the acoustic wave cell-sorting chip using a layer of silicone-polydimethylsiloxane.

According to Huang, two parallel transducers, which convert alternating current into acoustic waves, were placed at the sides of the chip.

As the acoustic waves interfere with each other, they form pressure nodes on the chip. As cells cross the chip, they are channeled toward these pressure nodes.

The transducers are tunable, which allows researchers to adjust the frequencies and create pressure nodes on the chip.

The study findings are published in the journal 'Lab on a Chip'.