Raman spectroscopy is sensitive to biochemical changes related to various cartilage injuries

Abstract

Raman spectroscopy is promising in vivo tool in various biomedical applications; moreover, in recent years, its use for characterizing articular cartilage degeneration has been developing. It has also shown potential for scoring the severity of cartilage lesions, which could be useful in determining the optimal treatment strategy during cartilage repair surgery. However, the effect of different cartilage injury types on Raman spectra is unknown. This study aims to investigate the potential of Raman spectroscopy for detecting changes in cartilage due to different injury types. Artificial injuries were induced in cartilage samples using established mechanical and enzymatic approaches to mimic trauma‐induced and natural degeneration. Mechanical damage was induced using surface abrasion (ABR, n = 12) or impact loading (IMP, n = 12), while enzymatic damage was induced using three different treatments: 30 min trypsin digestion (T30, n = 12), 90 min collagenase digestion (C90, n = 12), and 24 h collagenase digestion (C24, n = 12). Raman spectra were obtained from all specimens, and partial least squares discriminant analysis (PLS‐DA) was used to distinguish cartilage injury types from their respective controls. PLS‐DA cross‐validation accuracies were higher for C24 (88%) and IMP (79%) than for C90 (67%), T30 (63%), and ABR (58%) groups. This study indicates that Raman spectroscopy, combined with multivariate analysis, can discern different cartilage injury types. This knowledge could be useful in clinical decision‐making, for example, selecting the optimal treatment remedy during cartilage repair surgery.

In Situ Bending Reveals Simultaneous Enhancements of Strength and Ductility of Cortical and Cancellous Layers Induced by the Cartilage Layer

“…Specifically, under compressive stress, the molecular bond distance would shorten. According to the relationship between the force constant and the bond distance, the increased distance would cause the increment of vibration frequency, the spectral bands would correspondingly move to the high frequency bands . With regard to the neutral layer, before applying the bending load, the Raman shift of the peak position was measured as 2930.…”

“…According to the relationship between the force constant and the bond distance, the increased distance would cause the increment of vibration frequency, the spectral bands would correspondingly move to the high frequency bands. 23 With regard to the neutral layer, before applying the bending load, the Raman shift of the peak position was measured as 2930. Attributed to the stress-free condition of the neutral layer, the bending load did not induce significant Raman shift, as illustrated in Figure 6b, which indicated that the effect of the local bending load on the stress condition change in the neutral layer was negligible.…”

Assessment of Ligament Viscoelastic Properties Using Raman Spectroscopy

“…Raman spectroscopy is sensitive to changes in molecular composition which are affected by collagen network damage and other degenerative changes. 7 , 24 Hence, it was postulated that Raman spectroscopy may also yield useful information on the structural and functional properties of ligaments. Collagen is the major extracellular matrix (ECM) constituent in connective tissue and plays a crucial role in their functional properties.…”

“…In recent years, Raman spectroscopy has emerged as a viable tool for the study of OA and joint health. 19 This is due to its sensitivity to the changes in composition of diseased joint tissue, 24 even in early disease stages, and its suitability for in vivo assessment. While spectroscopic evaluation of the biomechanical properties of different knee tissues has been conducted previously, 1 , 20 , 28 Raman spectroscopy has not been thoroughly tested, particularly on ligaments.…”

Raman opportunities in the field of pathological calcifications

“…Their Raman experiments reveal the presence of bound water within the collagen component of connective tissue even after freeze-drying and its role in denaturation that is accompanied by or perhaps preceded with breakdown of the primary polypeptide structure. Finally, Shaikh et al [200] underlines the fact that Raman spectroscopy is able to provide biochemical details regarding potential for scoring the severity of cartilage lesions, which could be useful in determining the optimal treatment strategy during cartilage repair surgery.…”