Molecular processes and structural alterations in laser reshaping of cartilage

Abstract

Abstract:The effects of non-destructive laser irradiation on the structure and molecular processes in cartilage were studied using Raman microscopy, differential scanning calorimetry and biochemical analysis. A structural reorganization of the irradiated tissue similar to poliginization in polycrystalline solids was observed for the first time in a cartilage matrix. The difference in the Raman spectra of the irradiated and control samples was interpreted in term of a conformational alteration of glycosaminoglycan macromolecules in the reshaping mode. Laser induced modification of collagen macromolecules was not revealed by Raman spectroscopy. Thermal and biochemical analysis confirmed a preservation of triple helix for laser settings used for laserinduced stress relaxation and reshaping of cartilage.Microphotograph of the Group 3 sample with the two particles. Original magnification ×100, scale bar = 20 µm

Early detection of biomolecular changes in disrupted porcine cartilage using polarized Raman spectroscopy

“…Varying exposure times for each Raman spectra and possible varying GAG concentrations at different cartilage locations may have resulted in the varying significance of the GAG contribution to the Raman spectra. 13,30 Despite previous studies suggesting that GAG possesses neither intrinsic nor form birefringence except under the influence of certain dyes, 42,43 our polarized Raman spectra [arrows in Figs. 4(b) and 4(c)] revealed a distinct parallel dichroism in the GAG-associated pyranose band at 1042 cm − 1 that may be useful for characterizing structural changes of cartilage in tissue.…”

“…4(b)] show similar Raman spectral shapes and band positions to the rabbit nasal septa cartilage of rabbit, 30 except for the Raman band 957 cm − 1 associated with phosphate in the subchondral bone which was not reported. In our study, the phosphate Raman band (957 cm − 1 ) in the parallel polarized Raman spectra becomes visible after the porcine explants were impacted.…”

“…A maximum of four spectra on the same cartilage explants were obtained at various locations to reduce the chances of overheating, 30 and serious disturbances of the cellular structure. All cartilage explants were also kept moist with physiological saline solution during Raman measurements.…”

Effects of sample orientation in Raman microspectroscopy of collagen fibers and their impact on the interpretation of the amide III band

“…In several papers Raman spectroscopy and microspectroscopy have been employed to study pure collagen [3][4][5] as well as its presence in bone [6,7], cartilage [8], skin [9,10] and eye [11] tissues. In particular, Kazanci et al reported a polarization effect on the collagen-associated bands in Raman spectra of bone tissue [12].…”

“…Indeed, the relative intensity ratio of this doublet, typically assigned to two amide III vibrations, has been usually employed as an important marker for collagen conformation [3,4,[6][7][8][9][10][11][15][16][17].…”