Transmission FT-IR Chemical Imaging on Glass Substrates: Applications in Infrared Spectral Histopathology

Abstract

Fourier transform-infrared (FT-IR) chemical imaging in transmission mode has traditionally been performed on expensive mid-IR transparent windows such as barium/calcium fluoride, which are more fragile than glass, making preparation in the histopathology laboratories more cumbersome. A solution is presented here by using cheap glass substrates for the FT-IR chemical imaging, which has a high-wavenumber transmission window allowing measurement of the C-H, N-H, and O-H stretches occurring at ca. 2500-3800 cm(-1). The "fingerprint" region of the IR spectrum occurring below 1800 cm(-1) is not obtainable; however, we demonstrate that a wealth of information is contained in the high wavenumber range using 71 patients on a breast tissue microarray (TMA) as a model for investigation. Importantly, we demonstrate that the tissue can be classified into four basic tissue cell types and that using just the epithelial cells, reasonable discrimination of normal and malignant tissue can be found.

Development of a practical spatial-spectral analysis protocol for breast histopathology using Fourier transform infrared spectroscopic imaging

“…All evaluations to this point in this study have been performed on images collected by light transmission, which generally provides the best quality datasets. Other studies have reported using glass slides, 78 which involve a trade-off between practicality and reduction in spectral wavelength bandpass, or reflective glass slides, which require transflection model imaging. Another alternative is to use attenuated total reflection mode sampling, 79 which can offer higher spatial resolution 80 but requires good contact with the sample that can be cumbersome for translation.…”

Detecting bacteria contamination on medical device surfaces using an integrated fiber-optic mid-infrared spectroscopy sensing method

“…4. However, spectra from a non-reflective surface (transparent surface) such as transparent polyvinyl or clear glass (data not shown) are distorted and high absorption effects are observed in the spectral range lower than 1500 cm −1 in comparison with reflective or partially-reflective surfaces [23,[33][34][35]. At wavenumber greater than ∼1500 cm −1 non-reflective surface material are transparent to IR radiation.…”

Infrared imaging in histopathology: Is a unified approach possible?

“…Other interesting alternatives have been proposed such as using glass substrate and limiting the spectral range to the high mid-IR wavenumber window where glass is sufficiently transparent [8]. This may be a viable solution for some particular cases but will probably not be of general applicability as most of the fingerprint region of the spectrum is lost.…”