Cancer starts with little changes in DNA, slowly building until it becomes a problem. New microscopy techniques are beginning to show researchers what those subtle changes are, reports New Scientist's Linda Geddes. The researchers say that an understanding of these changes could lead to early detection tools. "Tracking those changes has been frustratingly beyond the reach of medicine," Geddes says. "They involve tweaks to structures that are less than 400 nanometers across, which is smaller than the wavelength of the visible light used in ordinary optical microscopy." So Northwestern University's Vadim Backman is trying something else — a method called partial wave spectroscopic microscopy, which works by analyzing the way a beam of light interacts with a cell. "As the beam travels through the cell it reflects off different structures within according to their density," Geddes says. "The pattern from the reflected light is used to reconstruct the nanoscale detail inside the cell." Using this approach, Backman has been able to show that cells that look healthy can actually have unusual chromatin densities that are not seen in cancer-free people.
Dec 03, 2011