Aug. 23, 1999 MANHATTAN -- Writing in the latest issue of Science magazine, released Aug. 19, Kansas State University chemist David Wetzel and co-author Steven LeVine of the University of Kansas Medical Center describe advances in the rapidly emerging technology, infrared microspectroscopy, and its increasing applications for biological and other research.
The American Association for the Advancement of Science publishes Science magazine, one of the most prestigious journals about scientific research.
The invited article by the two Kansas scientists, "Imaging Molecular Chemistry with Infrared Microscopy," appears in Techview. On the cover, a cross-section photomicrograph of a rat retina appears in color achieved with optical techniques only possible since December with the all-reflecting microscope.
Wetzel and LeVine have worked at the cutting edge of this technology since the modern infrared microscope was developed and patented in 1989. Almost immediately, Wetzel carried sectioned wheat samples to the inventor's labs for analysis on the new instruments, thus becoming one of the first researchers in the world to test its capability for analyzing biological materials.
The quality of the data from those first wheat experiments became the basis for a scientific presentation, and subsequent scientific publication.
According to Wetzel, inside a wheat kernel or other tissues, there are localized miniature biochemical factories with raw material, intermediate material and end products. "With an infrared microspectrometer, we could begin to see how each factory is working, and analyze it on the spot," he explained.
Infrared microspectroscopy combines a special infrared microscope, infrared spectrometer and computer. This instrumentation makes it possible to analyze the localized chemical content of extremely small specimen -- single cells, single fibers, single crystals, and botanical parts. The technical advance eliminated the need to grind up a sample or stain it. Instead, slicing it "thin enough" -- to 1/10th the thickness of a human hair -- is all that's needed to probe its chemistry.
Select wavelengths of infrared radiation that strike the target sample are either absorbed or transmitted by the molecules, thus providing a chemical signature. That infrared signature tells an analyst what's present and how much. Being able to achieve spatial resolution has been a long-time goal of scientists, and the microscope pinpoints the target of only a few microns. By analyzing a sample in a grid pattern, a map of localized chemistry of the molecules is developed that can be superimposed over the visible physical microstructure under study.
"We were invited by the Science editors to write this mini-review of the field in recognition of our research activities using this instrumentation," Wetzel said. "Our research results and presentation of the data have helped attract potential users from other fields of science."
Wetzel and LeVine's collaborative and on-going studies of the internal chemistry of biological molecules range "from grains to brains," Wetzel said.
Though most of their research was done at K-State and at KU, the Kansas scientists never hesitated to pack up their cell and tissue samples and travel to work on a prototype. Wetzel and LeVine provided feedback to the instrument makers, who responded with modifications like programmable mapping capability and custom data treatment software, now standard on today's instruments.
The Kansas researchers were the first to use the molecular microspectrometer for brain tissue research, successfully mapping the chemical boundaries between gray matter, white matter and basal ganglia of brain tissues. The results, published in Spectroscopy, introduced the technology to the scientific community.
"In a single decade, scientists have taken a technique developed for inspecting computer chips and investigating trace evidence from crime scenes, and began using it to study biological molecules of all kinds," Wetzel said. "Along the way, the needs of scientific research put demands on the instrumentation, and the manufacturers responded."
Their collaborative research has been funded by the National Science Foundation's Experimental Program to Stimulate Competitive Research. Individually, they have support from the Kansas Agricultural Experiment Station and the National Institutes of Health.
They were invited to serve as guest editors of a special edition of the international journal Cellular and Molecular Biology. The 270-page special edition contains 26 articles by 93 scientists at 53 institutions in eight countries. The landmark publication covered nearly all biological applications for the technology so far. They have written a book chapter for "Infrared and Raman Spectroscopy of Biological Materials," now in press.
"The way we get better at analyzing and imaging molecular chemistry in the microscope field is completely dependent on having access to new technology," says Wetzel. "We've been privileged to know and in some cases to work interactively with the instrument makers in this field. We've tried to take advantage of each new technological improvement within months of its development and use it to address our scientific research needs. It's been a very exciting decade."
Prepared by Kay Garrett. For more information contact David Wetzel at K-State's department of grain science and industry, Microbeam Molecular Spectroscopy Lab, department of grain science and industry Microbeam Molecular, at (785) 532-4094 (office), (785) 539-2509 (home) or e-mail Dwetzel@ksu.edu; and Steven LeVine, University of Kansas Medical Center, department of molecular and integrative physiology, at (913) 588-7420 (office), (913) 339-6395 (home) or e-mail email@example.com **** Sidebar: THE MANY USES OF INFRARED MICROSPECTROSCOPY
MANHATTAN -- It has been used in several nonbiological fields. For example: The computer and communication industries identify contaminants or explain failures in hard drives, silicon chips and optical sensing devices.
Petroleumgeologists can detect 1,000 year-old carbon dioxide bubbles encapsulated in slices of rock, findings that suggest oil's presence.
Forensics experts and crime labs analyze "trace evidence" -- single fibers, threads, blood samples, human hair. Automobile identification based on a paint fleck from a hit-and-run accident is routine now.
In the field of art preservation and authentication, museums such as the J. Paul Getty Museum and its Restoration Unit have used it to examine the Dead Sea scrolls and study cross-sections of paint on Dutch masterpieces; likewise, layers of wood in a priceless desk were analyzed and authentically restored
Material scientists investigate the composition of polymer laminates and composites.
Wetzel and LeVine foresee many future everyday uses for the emerging technology.
A recent query from an automobile manufacturer hints at its versatility: Could infrared microspectroscopy detect the depth of the sun's damage to automobile paint? Absolutely, Wetzel's investigation found.
Other possible uses might include: In human medicine, it may become the basis for objective screening tools for cancers in diagnostic pathology labs. Quality-control in manufacturing; plant breeding; drug identification; biotechnology; and materials and forensics.
Prepared by Kay Garrett.
ABOUT THE AUTHORS:
David L. Wetzel is a research analytical chemist in K-State's department of grain science and industry. He directs K-State's Microbeam Molecular Spectroscopy Lab. Much of his research involves describing localized chemical differences between or within different parts of plants. In some of his earliest studies of grasses, he was able to identify the presence of a class of chemicals called aromatic lignins, which, if present in large enough amounts, indicate the grass is much less digestible as livestock feed. That kind of chemical analysis can tell plant breeders at a very early stage in a breeding trial if it's on target.
Wetzel is a native of Rock Island, Ill., and a graduate of Rock Island High School.
Steven M. LeVine is a neuroscientist in the department of molecular and integrative physiology at the University of Kansas Medical Center. He studies the molecular chemical differences between normal and diseased brain tissue to understand the chemical mechanism of diseases like multiple sclerosis.
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