FTIR Imaging of Tissues: Techniques and Methods of Analysis

Abstract

In this chapter, we describe biomedical applications of infrared microscopic imaging applied to human tissue sections. the central focus is human diseases including cervical cancer, neurodegenerative pathologies, and dysfunctions of cardiac and liver tissues. In addition, we briefly describe the fundamentals of FtIR imaging instrumentation along with spectral pre-processing and hyperspectral image reconstruction. the chapter concludes with a summary of what is required to take FtIR imaging technology into the clinical environment.

Chemical imaging of a Symbiodinium sp. cell using synchrotron infrared microspectroscopy: a feasibility study

“…The FTIR spectra of DMSP and its precursors, methionine and cysteine (Fig. B), and the published literature (Dovbeshko et al ., ; Movasaghi et al ., ; Malek et al ., ), support our deduction that these bands arise from thiol and/or amino groups. Closer examination of the chemical images showed that the band at 2675 cm −1 is confined to the accumulation body only (Fig.…”

“…Absorption bands corresponding to the aliphatic stretching vibrations (3015–2850 cm −1 ) and the ester C = O stretches (1748 cm −1 ) of lipids are prominent features of region 1, although less intense in comparison to regions 2 and 3. The intense bands at 1120 cm −1 and 1190 cm −1 were difficult to assign but most likely arise from the C–O, C–C and/or CO–O–C stretches of carbohydrates, nucleic acids, amino acids and proteins (Malek et al ., ). However, we cannot rule out the possibility that they may also arise from the stretching vibrations of PO 2− in phospholipids given the obvious bands associated with lipid.…”

“…Region 3 has a noticeably more intense O‐H absorption band, which can be seen as a large broad band at 3350 cm −1 . The complex spectral region between 1300 and 1000 cm −1 has a similar profile to region 2 but is distinguished by a strong absorption band at 1230 cm −1 , which was assigned to PO 2 − stretching vibrations (Pohle et al ., ; Malek et al ., ).…”

“…Region 1, which corresponds to the amber coloured accumulation body (Figs. A–C), is characterised by bands assigned to S–H stretches (Malek et al ., ) at 2575 cm −1 and NH 3 + stretches (Dovbeshko et al ., ; Movasaghi et al ., ) at both 2675 cm −1 and 2800 cm −1 ; the localised nature of which can be clearly seen in the chemical images (Figs. B and C).…”

High-definition Fourier Transform Infrared (FT-IR) Spectroscopic Imaging of Human Tissue Sections towards Improving Pathology

“…The advances in FT-IR for tissue imaging have been driven in a large part by three key developments: 1) increased speed of data acquisition due to the availability of large Focal Plane Array (FPA) detectors which typically have thousands of IR sensitive detectors 1,2 , 2) development of advanced processing algorithms and computational power to handle large hyperspectral data sets 3 , and 3) modeling of FT-IR imaging systems to maximize spatial resolution 4,5 . There have been numerous high quality and very extensive articles reviewing the field of FT-IR spectroscopy recently [6][7][8][9][10][11][12][13][14][15][16] , in addition to a Nature Protocols paper that details the steps to obtain point spectra or maps from tissues 17 . In this paper, we will focus on the protocol to obtain images of tissues using a 128 x 128 FPA detector in a modified FT-IR system with high-definition capabilities.…”