Analytical and Bioanalytical Chemistry

, Volume 389, Issue 4, pp 1133–1142

Methodology for fiber-optic Raman mapping and FTIR imaging of metastases in mouse brains

  • Christoph Krafft
  • Matthias Kirsch
  • Claudia Beleites
  • Gabriele Schackert
  • Reiner Salzer
Original Paper

Abstract

The objectives of this study were to optimize the preparation of pristine brain tissue to obtain reference information, to optimize the conditions for introducing a fiber-optic probe to acquire Raman maps, and to transfer previous results obtained from human brain tumors to an animal model. Brain metastases of malignant melanomas were induced by injecting tumor cells into the carotid artery of mice. The procedure mimicked hematogenous tumor spread in one brain hemisphere while the other hemisphere remained tumor free. Three series of sections were prepared consecutively from whole mouse brains: dried, thin sections for FTIR imaging, hematoxylin and eosin-stained thin sections for histopathological assessment, and pristine, 2-mm thick sections for Raman mapping. FTIR images were recorded using a spectrometer with a multi-channel detector. Raman maps were collected serially using a spectrometer coupled to a fiber-optic probe. The FTIR images and the Raman maps were segmented by cluster analysis. The color-coded cluster memberships coincided well with the morphology of mouse brains in stained tissue sections. More details in less time were resolved in FTIR images with a nominal resolution of 25 μm than in Raman maps collected with a laser focus 60 μm in diameter. The spectral contributions of melanin in tumor cells were resonance enhanced in Raman spectra on excitation at 785 nm which enabled their sensitive detection in Raman maps. Possible reasons why metastatic cells of malignant melanomas were not identified in FTIR images are discussed.

Figure

FTIR image of 310 × 398 pixels obtained from an unstained, dried 10 μm tissue section of normal mouse brain. Colors represent the class assignments by cluster analysis

Keywords

Brain tumors Tissue classification Animal model FTIR imaging Raman mapping 

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Christoph Krafft
    • 1
    • 3
  • Matthias Kirsch
    • 2
  • Claudia Beleites
    • 1
  • Gabriele Schackert
    • 2
  • Reiner Salzer
    • 1
  1. 1.Institute for Analytical ChemistryDresden University of TechnologyDresdenGermany
  2. 2.Clinic for Neurosurgery, University HospitalDresden University of TechnologyDresdenGermany
  3. 3.Department of Materials and Natural ResourcesUniversity of TriesteTriesteItaly

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