:: By: Lydialyle Gibson

:: Photograph by Dan Dry

Investigations ::

Fast CARS

Justin Jureller, SM’00, PhD’06, expects researchers to come running this year as he and chemistry professor Norbert Scherer, SB’82, and postdoc Martin Lenz finish building a high-resolution microscope capable of peering into living tissue. Stretching the length of a Gordon Center lab table, the instrument (shown at right with, from left, Scherer, Lenz, and Jureller) uses coherent anti-Stokes Raman scattering (CARS) imaging, which generates a picture by detecting molecules’ vibrational resonances. Because different types of cells vibrate at specific frequencies, a CARS microscope can identify a sample tissue’s chemical makeup without requiring added dyes or fluorescent molecules. “It’s extremely noninvasive,” says Jureller, technical director at the Institute for Biophysical Dynamics’s nanobiology facility, which houses the CARS microscope.

The instrument’s applications are myriad and interdisciplinary, he adds, noting it may help study lipid membranes, cell interactions, biogenesis, vesicle transport, cell mobility, and cell morphology. A CARS microscope could, for instance, not only distinguish tumorous from nontumorous cells, but also malignant from benign. “There’s a gulf between basic science and basic instrument development,” Scherer says. ”Translating one to the other is critical.”

Developed for practical use in the 1990s, CARS microscopy hasn’t yet reached the commercial market, and Chicago’s instrument will be one of only a few in the country. It works by synchronizing two ultrafast lasers at different—and nearly infrared—frequencies. The laser pulses overlap to create a single beam that amplifies a particular vibrational signal from tissue molecules. “We choose what part of the spectrum we want,” Lenz says, “and create a laser color, or frequency, to match the resonances of the molecules we want to see.”