Applications of Vibrational Spectroscopy for Analysis of Connective Tissues

Abstract

Advances in vibrational spectroscopy have propelled new insights into the molecular composition and structure of biological tissues. In this review, we discuss common modalities and techniques of vibrational spectroscopy, and present key examples to illustrate how they have been applied to enrich the assessment of connective tissues. In particular, we focus on applications of Fourier transform infrared (FTIR), near infrared (NIR) and Raman spectroscopy to assess cartilage and bone properties. We present strengths and limitations of each approach and discuss how the combination of spectrometers with microscopes (hyperspectral imaging) and fiber optic probes have greatly advanced their biomedical applications. We show how these modalities may be used to evaluate virtually any type of sample (ex vivo, in situ or in vivo) and how “spectral fingerprints” can be interpreted to quantify outcomes related to tissue composition and quality. We highlight the unparalleled advantage of vibrational spectroscopy as a label-free and often nondestructive approach to assess properties of the extracellular matrix (ECM) associated with normal, developing, aging, pathological and treated tissues. We believe this review will assist readers not only in better understanding applications of FTIR, NIR and Raman spectroscopy, but also in implementing these approaches for their own research projects.

Mechanisms of reducing joint stiffness by blocking collagen fibrillogenesis in a rabbit model of posttraumatic arthrofibrosis

“…FTIR spectroscopy of tissue samples provides information about their composition and spatial distribution of analyzed macromolecules [ 39 ]. Here, we used this method to compare the relative collagen content in the scar tissues formed in the PCs and OCDs of the ACA-treated and CA-treated rabbits.…”

Compliance of the fish outflow tract is altered by thermal acclimation through connective tissue remodelling

“…This conclusion is supported by the lack of significant changes in our index of collagen coherency. Rather, we found shifts related to changes in collagen fibre density [ 41 – 43 ] that could be underpinned by changes in MMP activity. Following warm acclimation, we found an increase in MMP-2 activity, which was probably due an increased MMP-2 to proMMP-2 ratio.…”

“…Long-term temperature acclimation is associated with a change in the biochemical profile of heart tissue resulting from changes in protein composition, metabolic status and metabolite storage of the tissue [40] which can be assessed using non-biased FTIR spectroscopy. Indeed, FTIR has recently been used to characterize pathological changes in collagen fibre density associated with disease [41][42][43]. We investigated the mean spectral profiles from cold-and warm-acclimated fish bulbus arteriosus which showed the characteristic vibrational absorptions of collagen I (1080, 1377, 1429, 1611, 1628, 1657, 1678, 1690 cm −1 ) (figure 2a).…”

Brillouin and Raman Micro-Spectroscopy: A Tool for Micro-Mechanical and Structural Characterization of Cortical and Trabecular Bone Tissues

“…Raman spectroscopy has been used as a technique for assessing bone quality by the estimation of some important parameters [34][35][36], such as (i) the mineral-to-matrix ratio, evaluating the relative content of hydroxyapatite to the bone organic constituents, which is usually calculated using the intensity of ν 1 PO 4…”