Detection of depth‐depend changes in porcine cartilage after wear test using Raman spectroscopy

Abstract

Cartilage damage and wear can lead to severe diseases, such as osteoarthritis, thus, many studies on the cartilage wear process have already been performed to better understand the cartilage wear mechanism. However, most characterization methods focus on the cartilage surface or the total wear extent. With the advantages of high spatial resolution and easy characterization, Raman microspectroscopy was employed for the first time to characterize full-depth changes in the cartilage extracellular matrix (ECM) after wear test. Sections from the cartilage samples after wear were compared with sections from the control group. Univariate and multivariate analyses both indicated that collagen content loss at certain depths (20%-30% relative to the cartilage surface) is possibly the dominating alteration during wear rather than changes in collagen fiber orientation or proteoglycan content. These findings are consistent with the observations obtained by scanning electron microscopy and histological staining. This study successfully used Raman microspectroscopy efficiently assess full-depth changes in cartilage ECM after wear test, thus providing new insight into cartilage damage and wear.

Raman Spectroscopy-based Analysis of Cartilage Composition with Applications in Finite Element Modeling

“…Similarly found across all measurements in this thesis, and others involving cartilage [20,21,62,81,89],…”

“…This demonstrates the variability in separate samples -even from the same joint surface. This high amount of variability should be expected in most biological samples and appears to be a common aspect of Raman measurements in cartilage[20,21,81]. Apart from this characteristic the MCR deconvolved spectra were not expected to match perfectly.…”

Measurement of cartilage sub‐component distributions through the surface by Raman spectroscopy‐based multivariate analysis

“…This high amount of variability should be expected in most biological samples and appears to be a common aspect of Raman measurements in cartilage. [ 2,3,25 ] Apart from this characteristic the MCR deconvoluted spectra were not expected to match perfectly. Also present in the tissue are chondrocytes, hyaluronic acid, multiple collagen types and other proteins in minor quantities.…”

Raman Spectroscopy: Guiding Light for the Extracellular Matrix

“…Kumar et al also analyzed human OA cartilage using confocal Raman spectroscopy and demonstrated sensitivity to different grades of the disease (Kumar et al, 2015). Tong et al (2018) performed Raman spectral characterizations on porcine cartilage explants subjected to mechanical wear regimens, demonstrating a decrease in peak intensities corresponding to the protein backbone and amide bonds in collagen (817 and 1,670 cm −1 ). In an interesting novel analytical approach, Unal et al (2019) recently demonstrated that analysis of high wavenumber Raman spectroscopy (2,800 to 3,800 cm −1 ) can be used to detect the water fractions in articular cartilage (bound versus unbound water) and the elevated tissue swelling associated with OA - results that were correlated with MRI measurements.…”