Bone Typical Raman Bands and Parameters

960 cm has been shown to be inversely related to mineral maturity/crystallinity [2, 207]. 

As noted earlier, hard tissues are composite materials consisting of mineral and organic matrix. In Raman spectroscopic analysis, the organic matrix is identified by methylene side chains (CH2 at 1450 cm ), amide III ( 1200-1300 cm ), amide I ( 1620-1700cm ), phenylalanine (1002cm ) or the combined proline (921 and 855 cm ), and hydroxyproline (876 cm ) bands [2, 27, 208-210]. 

The main band representative of collagen is the amide I region from 1620 to 1700 cm , although it does encompass information from noncollagenous proteins, lipids, and proteoglycans (e.g., proteins with a-helix domains do contribute at 1645-1654 and at 1670 cm ) [23, 27, 208, 211, 212]. Lipids are identified by the CH vibrations at 1296 (CH2 twisting), 1440, and at 1465 cm (CH2 scissoring) [27]. 

Unlike FT-IR, the mineral/matrix ratio in Raman spectra may be expressed based on different bands, such as the V2P04/amide I ratio, V2P04/amide III ratio, or the v PO /combined proline and hydroxyproline (851 + 873 + 917 cm ) ratio [2, 210, 213]. The choice of parameters is dependent on the embedding material, instrumentation and the band sensitivity to orientation [33-35]. Other parameters that are commonly reported are the carbonate-to-mineral ratio from the B-type carbonate at 1071 cm and either the Vj or V2 phosphate bands [2, 

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