Imaging Mass Spectrometry of Intact Biomolecules in Tissue Sections - Proteomic and Metabolomic Approaches to Biomarker Discovery - page 384

FIGURE 1 Workflow for MALDI
imaging mass spectrometry. Sections
are taken from a tissue specimen and
collected onto a target plate or
a microscope slide for histological
staining. Matrix is applied via spray
coating, sublimation, or robotic spot-
ting. Spectra are collected in an
ordered array from the surface of the
tissue section. Ion images can be
generated from any of the signals in
the mass spectra.

manually apply matrix. 23 This approach has
been used successfully for imaging applications
but leads to the production of moderately large
crystals (20 e 100

may cause large crystals to be formed, limiting
somewhat the attainable spatial resolution. Drier
matrix application methods such as sublima-
tion 21,22

cient at extracting larger
biomolecules but result in much smaller matrix
crystals on the sample surface, allowing higher
spatial resolution to be achieved.
The simplest and most inexpensive approach
is through the use of an airbrush sprayer to

are less ef m) and suffers from a lower

degree of reproducibility between different
spray devices and individuals. Automated spray
devices such as the TM Sprayer from HTX Tech-
nologies and the ImagePrep from Bruker Dalton-
ics have been introduced that allow more

m