Listening to cells: scientists probe human cells with ultrasound pulses
February 7, 2013
Researchers from the University of Bordeaux in France used high-frequency sound waves to test the stiffness and viscosity of the nuclei of individual human cells to help answer questions such as how cells adhere to medical implants and why healthy cells turn cancerous.
“We have developed a new non-contact, non-invasive tool to measure the mechanical properties of cells at the sub-cell scale,” says Bertrand Audoin, a professor in the mechanics laboratory at the University of Bordeaux. “This can be useful to follow cell activity or identify cell disease.”
The technique, called picosecond ultrasonics, was initially developed to measure the thickness of semiconductor chip layers.
The researchers grew cells on a metal plate and then flashed the cell-metal interface with an ultra-short laser pulse to generate high-frequency sound waves. Another laser measured how the sound pulse propagated through the cells, giving the scientists clues about the mechanical properties of the individual cell components.
“The higher the frequency of sound you create, the smaller the wavelength, which means the smaller the objects you can probe” says Audoin. “We use gigahertz waves, so we can probe objects on the order of a hundred nanometers.” For comparison, a cell’s nucleus is about 10,000 nanometers wide.
In the coming years, the team envisions studying cancer cells with sound. “A cancerous tissue is stiffer than a healthy tissue,” notes Audoin. “If you can measure the rigidity of the cells while you provide different drugs, you can test if you are able to stop the cancer at the cell scale.”