An illustration shows the microfluidic device and its cell-moving sound waves. Photo by Feng Guo et al./MIT
BOSTON, Jan. 26 (UPI) -- "Acoustic tweezers" may pave the way for 3D printing living cell structures, allowing scientists to better design tissue implants for reconstructive surgery and the treatment of disease.
The tweezers aren't actually tweezers at all, but a new technology enabling researchers to manipulate cells using sound waves. The targeted sound waves act like tweezers, seizing single cells and moving them in three dimensions. But unlike tweezers, there is no direct contact.
The manipulating waves are created by a specially designed microfluidic device. First, a cell is trapped between two acoustic standing waves, waves of equal height. The point where the waves meet and trap the cell is called the "pressure node."
Researchers are able to move the pressure node and the cell trapped within it by changing each wave's wavelength and shifting their phase, the angle of each wave's origin. This allows 2D movement across a horizontal plane. A third wave can be introduced to manipulate the cell's vertical position via what's known as "acoustic levitation."
"We now have a good idea of what to expect and how to control the 3-D positioning of the acoustic waves and the pressure nodes, enabling validation of the method as well as system optimization," Ming Dao, a principal research scientist in MIT's Department of Materials Science and Engineering, told MIT News.
Manipulating cells without physical contact is a vital -- but until now missing -- component of tissue design. The recreation of natural tissue structure demands precise control, but scientists have struggled to find a way to manipulate cells without damaging and degrading them.
"The results presented in this paper provide a unique pathway to manipulate biological cells accurately and in three dimensions, without the need for any invasive contact, tagging, or biochemical labeling," explained Subra Suresh, president of Carnegie Mellon and former dean of engineering at MIT. "This approach could lead to new possibilities for research and applications in such areas as regenerative medicine, neuroscience, tissue engineering, biomanufacturing, and cancer metastasis."
The new technology -- detailed in the journal PNAS -- could soon be used for noninvasive single cell manipulation in a medical setting.