Compiled by Photonics Spectra staff
MILWAUKEE – A synchrotron-based imaging
technique delivers intensity a million times brighter than sunlight – and
offers high-resolution pictures of the molecular composition of tissues with high
speed and quality.
A team of researchers from the University of Wisconsin-Milwaukee
(UWM), the University of Illinois at Urbana-Champaign and the University of Illinois
at Chicago demonstrated the capabilities of the new method, led by Carol Hirschmugl,
a physicist at UWM. Along with UWM scientist Michael Nasse, Hirschmugl built a facility
called Infrared Environmental Imaging (IRENI) to perform the technique at the Synchrotron
Radiation Center at the Madison campus of the University of Wisconsin. The technique
provided by the facility employs multiple beams – instead of just one –
of synchrotron light to illuminate a state-of-the art camera.
IRENI cuts the amount of time required to image a sample from
hours to minutes while quadrupling the range of the sample size and producing high-resolution
images that do not have to be tagged or stained as they would with an optical microscope.
Revealing the molecular composition, structure and chemistry of a tissue sample,
IRENI enables users to see the distribution of function groups, such as proteins,
carbohydrates and lipids.
IRENI-generated images (right) are 100 times less pixelated than those created by conventional infrared imaging (left). The difference is the result of multiple synchrotron beams, which provided enough light to obtain a detailed image of the sample. With the technique, the quality of the chemical images is now similar to that of optical microscopy. Courtesy of Carol Hirschmugl and Michael Nasse, University of Wisconsin-Milwaukee.
The unique features of the synchrotron make it a versatile light
source for spectroscopy. Streams of speeding electrons emit continuous light across
the entire electromagnetic spectrum so that researchers can access whatever wavelength
is best absorbed for a particular purpose. The team used the mid-IR range to form
graphic fingerprints of biochemically important molecules.
Using 12 beams of synchrotron light in this range allows researchers
to collect thousands of chemical fingerprints simultaneously, producing an image
that is 100 times less pixelated than in conventional IR imaging. The team tested
the technique on breast and prostate tissue samples to determine its potential for
diagnosing cancer and other diseases. With unprecedented detail, it detected features
that distinguish epithelial cells, in which cancer begins, from stromal cells, which
are found in deeper tissues.
The technique could open the door to a broad spectrum of applications
in medicine, pharmaceutical drug analysis, art conservation, forensics, biofuel
production and advanced materials such as graphene, Hirschmugl said.
The team’s findings, which were published online March 20,
2011, in Nature Methods (doi: 10.1038/nmeth.1585), could lead to synchrotron-based
imaging that can monitor cellular processes from simple metabolism to stem cell