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The

(invisible) light fantastic

T

hink of it as a wonder tool that yields high-definition pictures using light that isn’t visible. Physicist Carol Hirschmugl has developed a device, called IRENI, that not only reveals the kinds of molecules in a tissue sample and how they are changing, but also offers pictures with exceptional clarity. Among the scores of potential uses for this futuristic microscope is capturing the moment cancer cells spread—in a fraction of the time and with greater accuracy than before. It may also be a promising way to monitor other cellular processes, improve biofuel production or advance materials research.

RESEARCH REPORT 2012

“Since IRENI reveals the molecular composition of a tissue sample, you can choose to look at the distribution of functional groups, such as proteins, carbohydrates and lipids,” says Hirschmugl.

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Conventional infrared imaging can identify molecular structures, but the images are very blurry. Optical microscopes render sharp images, but tissue samples have to be stained in order for specific structures to be seen.

Hirschmugl had been using synchrotron radiation for a variety of experiments for 20 years before developing IRENI. A kind of racetrack for electrons, a synchrotron accelerates electrons to the speed of light until they emit light at all wavelengths, both visible and not. For IRENI, Hirschmugl employs just the mid-infrared range of the light from the synchrotron. But instead of using one beam, she uses 12 to illuminate a state-of-the-art camera. Light in the mid-infrared range is absorbed at thousands of locations on the sample, providing an equal number of graphic “fingerprints.” Taken together, they form a less-pixilated image. Hirschmugl is now seeking support to create “mini-synchrotrons” for use in medical facilities.

UWM Research Report 2012  

UWM faculty, staff and students are following many paths to creating new knowledge in diverse fields.