TITLE continued
Tech Intelligence
by Mike May AL
AL
Imaging MS Technology Seeing the compounds and their distribution in samples
Looking at a slice of tissue under a microscope reveals structures, especially ones marked with dyes or other indicators, but what else is there? The more slices that scientists study, thte more they wonder what makes up the structures. You can find out with imaging mass spectrometry (IMS)—a technology also known as MS imaging.
In matrix-assisted laser desorption ionization (MALDI) IMS, an ordinary tissue section is processed as usual for MALDI MS. Then, it is raster- scanned with a laser to generate a spatial map of MS data. The same slide is then stained for microscopy and imaged. The MS and imaging data sets can be combined.
“IMS is different from other imaging modalities in that it is capable of mapping hundreds to thousands of compounds, label-free, from sam- ples such as thin tissue sections,” says Shannon Cornett, market manager for life science imaging at Bruker Daltonics (Billerica, Mass.). “In contrast to other mass spectrometry techniques, IMS is unique in that it produces spatial maps of each compound detected that shows where it is localized within the sample along with relative abundance.”
Some facilities focus on expanding the use of IMS. “The National Re- search Resource for Imaging Mass Spectrometry was established in 2011 at Vanderbilt University within the mass spectrometry research center through funding from the National Institute of General Medi- cal Sciences,” says Danielle Gutierrez, project and communications manager at the center (Nashville, Tenn.). “The resource is directed by Richard Caprioli, who pioneered the development of IMS beginning in 1997.” He adds, “A driving goal of the resource is to advance imaging capabilities for the application of IMS to important biological questions and for implementation of the technology by nonexpert users within the scientific community.”
IMS can be applied to many research projects. At Vanderbilt, says Guti- errez, “The majority of imaging projects within the resource address biological and clinical issues for which the application of IMS can lead to a deeper understanding about the molecular basis of disease.” Other sci- entists around the world also use IMS, and a team of Japanese scientists used it to study the differentiation of stem cells.1
The use of IMS is only beginning, but some of the results already let us explore areas that we could not imagine just a few years ago. Even now, a search of “imaging mass spectrometry” turned up more than
AMERICAN LABORATORY 44
This high-resolution MALDI image shows three selected phospholipid ions in transverse section of rat brain cerebellum. (Image courtesy of Bruker Daltonics.)
JANUARY/FEBRUARY 2017
800 articles on PubMed. That’s already a pretty good start at using IMS in research.
Clinical opportunities “Over the past few years, two applications have driven interest and
development of MALDI imaging,” Cornett says. The first is biomarker dis- covery within the larger scope of clinical research. “In a discovery study, cohorts of samples are analyzed by MALDI imaging and the molecular fingerprints from different regions are examined for molecular changes associated with each,” Cornett explains. “Clinical samples are analyzed by MALDI imaging in order to gain a better understanding of biochemi- cal processes associated with disease development as well as to identify potential molecular markers that may be diagnostic of disease state, a positive or negative response to treatment, etcetera.” However, this kind of research has also been used to study nonclinical samples, including animals, insects, microorganisms and plants.
The second application driving IMS, according to Cornett, is “the pre- clinical imaging of dosed therapeutics and their metabolites in support of drug development. … Compared to traditional autoradiographic imaging, MALDI imaging—being mass spectrometry based—can dif- ferentiate a parent drug molecule from metabolites and the hundreds
by author
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68