mass spectrometry imaging

1. 17/22/2017

2. MASS SPECTROMETRY
IMAGING
Presented: by
Fayaz Hussain Chandio
National Centre of Excellence in
Analytical Chemistry
University of Sindh
Jamshoro
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3. Overview
 Introduction
 History
 Instrumentation
 Working principle
 Modes
 Applications
 Conclusion
 Reference
 Acknowledgement
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4. Introduction
 MSI a Valuable analytical tool, enables 2D imaging.
 Chemical Imaging of small molecules to intact
proteins, directly from tissue surface.
 Mapping of proteins, lipids, and metabolites in
biological tissue in morphological context.
 Discriminates the spatial distribution ( 2D ) of
biomolecules and biomarkers, biological responses
and diseases are better understood.
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5. Continue…
 Label free imaging technique, to visualize complex
biomolecules and whole cellular snapshots.
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6. History
 SIMS imaging was theoretically invented in 1949
by Herzog and Viehb of Vienna University.
 The first SIMS device was completed by Liebel and
Herzog in 1961.
 In 1997, the group of Dr. Caprioli of Vanderbilt
University presented the first paper regarding
MALDI-MS imaging.
 DESI imaging first reported by the group of Dr.
Cooks. Dr. Heeren, reported the stigmatic type
of IMS instrument in 2006.
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7. Continue ….
 Recently, first developed high-resolution IMS
(Mass microscopy), such as nanoparticle-assisted
laser desorption/ionization (Nano-PALDI), for
microscopic observation has been developed.
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8. Instrumentation
 Major MS hardware companies like Shimadzu,
Thermofisher Scientific etc. producing modern
MS instruments, which are adopted for MSI.
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9. Simple construction of MS
ion source
spectrum
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Sample
Mass ionizer
Mass
analyzer
Ion detector

10. MSI workflow chart
• f
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11. Ionization sources for MSI
 Matrix-Assisted Laser Desorption
 Secondary Ion Mass Spectrometry
 Desorption Electrospray Ionization
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12. Matrix Assisted Laser
Desorption Ionization Source
 MALDI is a ‘‘soft ionization technique”.
 Intense pulses of U.V laser used.
 Pharmacodynamics and toxicodynamics in tissue
have been studied by MALDI imaging.
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13. Continue…..
 The sample to be analyzed is dissolved in
solvent then mixed with matrix that absorb laser
radiation and ionize Analytes.
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14. Secondary ion Mass Spectrometry
 SIMS MS is the ‘‘oldest’’ IMS technique (1960s ).
 A beam of primary ions , monoatomic ( Bi+, Au+,
In+) is used.
 Analyzing solid surface and thin films sputtering
the surface with a focused primary ion beam
and collecting and analyzing ejected secondary
ions .
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15. Continue….
 SIMS is widely regarded as one of the most
sensitive to the sample and it is normally no more
than 1-3 nm thick.
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16. Desorption Electrospray Ionization
 DESI is one of the ambient mass spectrometry
techniques and allows for rapid analysis of the
sample in its original state.
 used for analysis of animal and plant tissues and
cell culture samples, mainly peptides.
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17. MASS ANALYZERS USED IN
(MSI):
There are three types of mass analyzers currently in use and
commercially available for imaging MS experiments.
I. TOF analyzer
II. Fourier transform ion cyclotron resonance mass
spectrometry (FT-ICR-MS)
III. Quadrupole mass analyzer
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18. TOF analyzer
 High throughput.
 In MALDI MSI for best results TOF is used.
 Typical flight times are 1to 30 µs.
 Ease of the accessibility of the ion source and
virtually unlimited mass range.
 limited resolution and sensitivity.
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19. Fourier transform ion cyclotron
resonance
 Higher level of resolution.
 High accuracy in mass determination.
 All ions are detected simultaneously.
 Due to high resolution, extremely useful to identify
isotopic peaks.
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20. Detectors
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 Photomultiplier.
 Micro channel plates.
 Electron multiplier.
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21. Workflow
 Important steps in MSI for visualizing molecules
 Sample Preparation
 Matrix Desorption
 Measurement
 Data analysis/ Image Generating.
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22. Sample Preparation
 Cell( Bacterial colonies identification) and
tissue analysis.
 Analysis of whole body sections.
 Initially disectioninig of tissues.
 Flash freezing, cryosectioning, and optimal
processing of the transferred tissue are required,
Washing cell with isotonic sugar solution.
 preserved(frozen) or fresh tissues may be used.
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 Morphology of tissues is main concern in both
cases.
 Tissue are sectioned into 5-20µm ( Ionization)
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24. Matrix Desorption
 The matrix solution is prepared by choosing a
solvent in which the Matrix material is easily
dissolved.
 The analyte is typically dissolved in an aqueous
solution.
 Solvent slowly evaporates, matrix crystals are
formed.
 Automatic depositing of small droplets of matrix
solution with robotic device e.g.. Chemical Inject
printer.
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25. Different matrix materials
 Choice of matrix used, totally depends on sample
to be analyzed:
 Sinapic acid (SA).
 9-aminoacridine acid.
 4-hydroxy-α-cyanocinnamic acid (HCCA).
 2,5-dihydroxybenzoic acid (DHB).
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26. Continue….
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Mainly used matrixes

27. Measurements/Mass analysis &
analyte localization.
 MSI requires transferring solid state Analytes into
the gas phase.
 Matrix coated sample should be measured as soon as
possible to avoid molecular degradation.
 MALDI-MSI is two dimensional technique, the
measurement region and scan pitch which decide
spatial resolution of image need to be fixed
before measurement is taken.
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28. Image generation
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30. Continue….
Visualization software packages that can rapidly and
efficiently analyze enormous spectra have been
developed.
 Bio Map
 Flex image
 Image quest
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31. Modes Of MSI
There are two modes
 Microprobe
 Microscope
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32. Microprobe
 This approach is technically easier and most
imaging spectrometers operate in this mode.
 It uses a highly focused ionization source and
every individual pixel of the image is
measured separately.
 Ionization beam strikes a small localized
region of surface and the ionized species are
separated according to their m/z ratio and
detected.
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33. Microscope
 In this case, the laser or primary ion beam is
irradiated with a larger area, typically 100-300
μm in diameter.
 Microscope mode can reduce analysis time.
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35. Applications
 Imaging of cells, tissues, biomolecules.
 Drug localization in tissue.
 Biomarker discovery.
 Crime scene investigation- human finger printing .
 Cancer research.
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36. Conclusion
IMS is rapidly developing field of analytical science,
demonstrating promising results in industry and in
fundamental science and applied science. And an
essential technique for molecular imaging because it
allows direct analysis of biomolecules in their original
Morphological context.
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37. References
 Int. J. Mol. Scie. 2013, 14, 11277-11301; doi:10.3390/ijms140611277
(www.mdpi.com/journal/ijms
 Emerging Technologies in Mass Spectrometry Imaging
Julia H. Jungmann and Ron M.A. Heeren*
 FOM-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The
Netherlands.
 Imaging with Mass Spectrometry
M. L. Pacholski and N. Winograd*
Department of Chemistry, Penn State University, 184 Materials
Research Institute Building, University Park, Pennsylvania 16802
 Skoog West Whloer Instrumental Analysis of Analytical Chemistry, Mass
Spectrometry chapter 20, pages 498-534.
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38. Acknowledgement
I am thankful to Almighty ALLAH Who is
most Merciful and Beneficent
I am indebted to my respected Sir Prof. Dr.
Shahabuddin Memon for his kind support, and also to
my seniors scholars for helpful discussions and a critical
review of the manuscript.
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39. Thank You…
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