Newswise — Philadelphia, Pa. – Sound waves are widely used in medical imaging, such as when doctors take an ultrasound of a developing fetus. Now scientists have developed a way to use sound to probe tissue on a much tinier scale. Researchers from the University of Bordeaux in France deployed high-frequency sound waves to test the stiffness and viscosity of the nuclei of individual human cells. The scientists predict that the probe could eventually 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 work will be presented at the 57th Annual Meeting of the Biophysical Society (BPS), held Feb. 2-6, 2013, in Philadelphia, Pa.
The technique that the research team used, called picosecond ultrasonics, was initially applied in the electronics industry in the mid-1980s as a way to measure the thickness of semiconductor chip layers. Audoin and his colleagues, in collaboration with a research group in biomaterials led by Marie-Christine Durrieu from the Institute of Chemistry & Biology of Membranes & Nano-objects at Bordeaux University, adapted picosecond ultrasonics to study living cells. They 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.
The team faced challenges in applying picosecond ultrasonics to study biological systems. One challenge was the fluid-like material properties of the cell. “The light scattering process we use to detect the mechanical properties of the cell is much weaker than for solids,” says Audoin. “We had to improve the signal to noise ratio without using a high-powered laser that would damage the cell.” The team also faced the challenge of natural cell variation. “If you probe silicon, you do it once and it’s finished,” says Audoin. “If you probe the nucleus you have to do it hundreds of times and look at the statistics.”
The team developed methods to overcome these challenges by testing their techniques on polymer capsules and plant cells before moving on to human cells. 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.”
Presentation # 991-Plat, “Listening to cells: A non-contact optoacoustic nanoprobe,” will take place at 8:45 a.m. on Monday, Feb. 4, 2013, in the Pennsylvania Convention Center, Room 113C. ABSTRACT: http://tinyurl.com/a3a8oxs
This news release was prepared for the Biophysical Society (BPS) by the American Institute of Physics (AIP).
ABOUT THE 2013 ANNUAL MEETINGEach year, the Biophysical Society Annual Meeting brings together over 6,000 research scientists in the multidisciplinary fields representing biophysics. With more than 3,900 poster presentations, over 200 exhibits, and more than 20 symposia, the Annual Meeting is the largest meeting of biophysicists in the world. Despite its size, the meeting retains its small-meeting flavor through its subgroup meetings, platform sessions, social activities, and committee programs.
The 57th Annual Meeting will be held at the Pennsylvania Convention Center (1101 Arch Street, Philadelphia, PA 19107). For maps and directions, please visit: http://www.paconvention.com/explore-philadelphia/directions-and-parking.
QUICK LINKSMeeting Home Page: http://www.biophysics.org/2013meeting/Main/tabid/3523/Default.aspx Housing and Travel Information: http://www.biophysics.org/2013meeting/AccommodationsTravel/HotelInformation/tabid/3621/Default.aspx Program Abstracts and Itinerary Planner: http://www.abstractsonline.com/plan/start.aspx?mkey=%7B763246BB-EBE4-430F-9545-81BC84D0C68C%7D
PRESS REGISTRATIONThe Biophysical Society invites credentialed journalists, freelance reporters working on assignment, and public information officers to attend its Annual Meeting free of charge. For more information on registering as a member of the press, contact BPS Director of Public Affairs and Communications Ellen Weiss at email@example.com or 240-290-5606, or visit http://www.biophysics.org/2013meeting/Registration/Press/tabid/3619/Default.aspx. Press registration will also be available onsite at the Pennsylvania Convention Center in the Biophysical Society’s meeting office, Room 304VIP.
ABOUT BPSThe Biophysical Society (BPS), founded in 1958, is a professional scientific society established to encourage development and dissemination of knowledge in biophysics. The Society promotes growth in this expanding field through its annual meeting, monthly journal, and committee and outreach activities. Its 9000 members are located throughout the U.S. and the world, where they teach and conduct research in colleges, universities, laboratories, government agencies, and industry. For more information on the Society or the 2013 Annual Meeting, visit www.biophysics.org.
For more information, please contact:Ellen R. WeissDirector of Public Affairs and Communicationseweiss@biophysics.org240-290-5606