Detection of endogenous biomolecules in Barrett's esophagus by Fourier transform infrared spectroscopy

Abstract

Fourier transform infrared (FTIR) spectroscopy provides a unique molecular fingerprint of tissue from endogenous sources of light absorption; however, specific molecular components of the overall FTIR signature of precancer have not been characterized. In attenuated total reflectance mode, infrared light penetrates only a few microns of the tissue surface, and the influence of water on the spectra can be minimized, allowing for the analyses of the molecular composition of tissues. Here, spectra were collected from 98 excised specimens of the distal esophagus, including 38 squamous, 38 intestinal metaplasia (Barrett's), and 22 gastric, obtained endoscopically from 32 patients. We show that DNA, protein, glycogen, and glycoprotein comprise the principal sources of infrared absorption in the 950-to 1,800-cm ؊1 regime. The concentrations of these biomolecules can be quantified by using a partial leastsquares fit and used to classify disease states with high sensitivity, specificity, and accuracy. Moreover, use of FTIR to detect premalignant (dysplastic) mucosa results in a sensitivity, specificity, positive predictive value, and total accuracy of 92%, 80%, 92%, and 89%, respectively, and leads to a better interobserver agreement between two gastrointestinal pathologists for dysplasia ( ‫؍‬ 0.72) versus histology alone ( ‫؍‬ 0.52). Here, we demonstrate that the concentration of specific biomolecules can be determined from the FTIR spectra collected in attenuated total reflectance mode and can be used for predicting the underlying histopathology, which will contribute to the early detection and rapid staging of many diseases.dysplasia ͉ pathology ͉ optical biopsy ͉ diagnostics

Discrimination of human stem cells by photothermal microspectroscopy

“…Covalently bonded atoms absorb IR radiation corresponding to the specific resonant frequencies of their vibrational motions 24 . It is on this basis that FTIR spectroscopy can be used for characterisation of biological materials such as cultured cells or tissue sections.…”

“…The main wavenumbers responsible for the separation of spectra from SCs and differentiated cell types are those in the region of 1710-1700 cm -1 (figures 6,7 and 8), around of 1590 cm -1 (figures 7 and 8), the region of 1480 cm -1 ( figure 7 and 8 is associated with sugar ring vibrations 26 and C-O and C-C stretch in DNA 24 .…”

Shining light on Barrett’s esophagus

“…Recent work by Wang et al has shown that FTIR-ATR measure ments can be used to identify dysplastic and nondysplastic (metaplastic) changes in BE biopsies, with greater diagnostic accuracy than conventional histopathologic interpretation [30]. However in this study, measurements were performed with limited spatial resolution in the horizontal plane, using biopsy samples of approximately 1-mm diameter.…”

FT-IR spectroscopy supported by PCA–LDA analysis for the study of embryonic stem cell differentiation

“…We should add that in the nucleic acid spectral region we observed also the absorption bands of glycogen around 1032 and 1022 cm −1 (C-O-H bending), 1081 cm −1 (C-C stretching) and 1154 cm −1 (C-O stretching) [30], whose intensities increase starting at day 7 of differentiation ( Fig. 1).…”