Tuesday, May 20, 2008

Looking into Live Cells at Nanoscale Resolution

Continued from page 1

By Katherine Bourzac

The Max Planck group developed a way to get around light's fundamental limitations by using two beams instead of one. The first light beam plays the same role--and is the same spot size--as light in a conventional microscope. It moves through the cell under study, exciting fluorescently labeled molecules inside the cell to fluoresce. The second beam "sculpts" the first, says Hell, inhibiting fluorescence created by the edges of the first beam. That reduces the effective spot size to 40 to 45 nanometers in diameter.

Fitzmaurice says that molecular-resolution microscopy will improve patient care down the line. "The focus has been on molecular defects in disease, but to really understand them you've got to see them in the cell," she says. She believes that nanoscale resolution microscopy will also play an important role in advancing personalized medicine. For example, scientists have identified specific biomarkers that help predict a cancer patient's prognosis, but not all patients with a particular biomarker respond similarly to the same treatments. Using Hell's new microscope and others to come, biologists can do the basic research needed to understand how proteins and other molecules interact and, ultimately, to identify more precise predictors of disease.

And in the future, microscopes with nanoscale resolution might be used in hospital labs to perform truly personalized medicine. Sedat says that the next level for nanoscale resolution microscopy is to develop it for imaging not only single cells but also tissues such as surgical biopsies. "I believe we're on the precipice of some important new directions for light microscopy," he says.