Researchers at Pennsylvania State University have developed a new prototype cell-sorting device which uses sound waves to arrange cells far more efficiently than before. The advance in efficiency presents the possibility that future medical analytical devices could be scaled-down to a size much smaller than is currently the case.

The prototype device uses two sound waves, which act as acoustic “tweezers” to sort a continuous flow of cells on a chip around the size of a dime. The researchers alter the frequency of the sound waves to direct the paths of the cells as desired, allowing the cells to be organized into five or more channels – this contrasts with the current limit of just two channels in one step which is true of most existing medical analytical devices.

It is believed that the increased capability will allow more cell types to be analyzed simultaneously, paving the way for future medical analytical devices to become smaller, more efficient, and less expensive.

"Today, cell sorting is done on bulky and very expensive devices," said Tony Jun Huang, associate professor of engineering science and mechanics, Penn State. "We want to minimize them so they are portable, inexpensive and can be powered by batteries." Huang also added that sound waves for cell sorting is less likely to damage cells than current techniques, which also produce aerosol gases, requiring extra safety precautions.

The device was initially tested by sorting a stream of fluorescent polystyrene beads into three channels, and this experiment was subsequently followed by a test which involved the researchers successfully sorting human white blood cells affected by leukemia into five separate channels. However, even these five channels do not represent the absolute limit of the device's capabilities.

"We can do more," enthused Huang. "We could do 10 channels if we want, we just used five because we thought it was impressive enough to show that the concept worked."

In the future, the Penn State cell-sorting device could be used for various types of analysis, including blood and genetic testing in biological, genetic and medical labs. The ultimate goal of the project is a portable, inexpensive, battery-powered unit.