Page 18 - Vibrational Spectroscopic Imaging for Biomedical Applications

xvi Pr ef a c e

integration times to do measurements at subcellular level, such as
sensing DNA hybridization, protein binding, etc. However, the
reproducibility of the surface enhancement factor is still disputed.
Another recent technique in Raman spectroscopy is coherent anti-
Stokes Raman scattering (CARS) microscopy, which is a nonlinear
imaging technique that offers chemical selectivity through vibrational
sensitivity. Recent developments in ultrafast light sources and
improved detection schemes have advanced CARS microscopy as a
useful imaging tool for biomedical applications.
In this book, a large number of enthusiastic spectroscopists,
including biochemists and clinicians, have discussed the latest develop-
ments in the aforementioned vibrational spectroscopic imaging. This
book would give a broad overview of the recent progress in aspects
like instrumentation, detector technology, novel modes of data
collection, and data analysis (multivariate). Emphasis has been given
on applications in the biomedical arena and to assess progress in the
fields.
Scientific developments in FTIR and Raman spectroscopic imaging
techniques, high-throughput tissue microarray (TMA) sampling, and
multivariate data analysis have been instrumental in accelerating this
imaging technique for the applications in histopathologic imaging for
cancer diagnosis and research. Chapter 1 is about automated breast
histopathology using FTIR spectroscopic imaging techniques. The
authors have employed multivariate segmentation approach, based
on a modified bayesian classifier to FTIR spectral images acquired
from human breast tissue microarray. The results discussed here
demonstrate promising results for reliable epithelium and stromal
recognition. Chapter 2 describes the novel instrumentation and
biomedical experiments that would provide an opportunity to
measure in situ (in vivo) kinetics of pathological mineralization.
Biomedical application of synchrotron IR microspectroscopy—
studying calcium-containing crystals in cartilage from human samples
and model systems—has been reviewed. The detailed description
about the IR synchrotron beamline design and implementation of
IRENI (IR Environmental Imaging) at the Synchrotron Radiation
Center (Stoughton, Wisconsin) is discussed. Chapter 3 describes the
preparation of tissues and cells for infrared and Raman spectroscopy
and imaging. The importance of sample preparation is described in
detail because the experimental design can have significant
implications for the interpretation of spectra and thus for their
biochemical relevance as well as the spatial distribution of biomolecules
in imaging studies.
Among the different sampling IR imaging techniques, transmission
mode imaging is the most common, while reflection-absorption is
also widely practiced. In recent times, ATR imaging has become a
common choice of measurement in some research groups. The reason
being that it allows users to work with relatively thick sample sections