Table 1.
A list of primary Raman metrics along with their method of determination and characterization that influences how they are interpreted.
| Metric | Measurement | Method | Characterization | Ref |
|---|---|---|---|---|
| Mineral-to-matrix ratio | ν1PO4/amide I | Peak intensity ratio (PI) | MMR was significantly higher in interstitial vs. osteonal tissue, except when determined by ν1PO4/Amide I | 29 |
| ν1PO4/amide III | ||||
| ν1PO4/Proline | ||||
| ν1PO4/CH2-wag | ||||
| ν1PO4/(Pro + Hyp) | Integrated peak area ratio (IA) | Each MMR reciprocally correlated with ash fraction, R2 = 0.894 to 0.976a | 118 | |
| ν1PO4/amide I | ||||
| ν1PO4/amide III | ||||
| ν1PO4/Phe | ||||
| ν1PO4/CH2-wag | ||||
| ν2PO4/amide III | IA ratio | MMR directly correlated with the % weight of Ca from qBEI, R2=0.75 | 105 | |
| ν1PO4/Phe | PI ratio | Direct correlation between RS and FTIR, R2 = 0.8331 | 119 | |
| ν1PO4/amide I | PI & IA ratios | MMR linearly correlated with vBMD from μCT, r=0.709; Raman-PI ratio linearly correlated with IR-IA ratio | 120 | |
| ν1PO4/(Pro+Hyp)b | ||||
| ν1PO4/amide I | IA ratio | Assessed from the cortical bone of young rats, MMR increases with tissue age | 121 | |
| ν1PO4/amide I | IA ratio | Higher MMR but lower ash fraction in cortical bone from diabetic ZDSD rats vs. non-diabetic Sprague-Dawley rats | 122 | |
| ν1PO4/CH2-wag | ||||
| ν1PO4/amide I | PI ratio | Higher MMR in cortical bone from diabetic ZDSD rats vs. non-diabetic Sprague-Dawley rats but no difference in Ct.TMD between groups | 123 | |
| ν1PO4/Pro | ||||
| Carbonate substitution | ν1CO3/ν1PO4 | PI ratio | RS and FTIR did not correlate | 119 |
| ν1CO3/ν1PO4 | IA ratio | Carbonate-phosphate ratio highly positively correlated with carbonate percentage (R2 = 0.965) | 55 | |
| ν1CO3/ν1PO4 | IA ratio | Carbonate in HA of mouse cortical bone significantly increased by 6.4%, on average, from 4–5-mo. to 19-mo. | 124 | |
| ν1CO3/ν1PO4 | PI ratio | Carbonate in HA of rat cortical bone significantly increased by 1.75%, on average, from 12-mo. to 24-mo. and was higher within the outer tissue than within the inner tissue of the midshaft | 125 | |
| Crystallinity | FWHM[ν1PO4]−1 | Maximum intensityc | Crystallinity directly correlated with c-axis of the crystal as determined by X-ray diffraction of human bone, buffalo enamel, boar tusk, and HA, R2 = 0.992 | 126 |
| FWHM[ν1PO4]−1 | ν1PO4 peak = 1 | Crystallinity of mouse cortical bone significantly increased by 1.9%, on average, from 4–5-mo. to 19-mo. | 124 | |
| FWHM[ν1PO4]−1 | Peak intensity | Crystallinity increased as mouse age increased: 4-wk, 10-wk, and 24-wk; fluoridation reduced crystallinity | 127 | |
| FWHM[ν1PO4]−1 | Peak intensity | Direct correlation between RS and FTIR, R2 = 0.8589 | 119 | |
| FWHM[ν1PO4]−1 | Maximum intensityd | High correlation of ν1PO4 peak position R2 = 0.92 and ν1PO4 FWHM R2 = 0.80 with apatite crystallite size assessed by XRD | 17 | |
| FWHM[ν1PO4]−1 | Peak intensity | Crystallinity decreases in femoral cortical bones of the rats with chronic kidney disease (CKD) owing to the increased Mg/Ca ratio in the hydroxyapatite | 128 |
a
y = C/(100-x); range identified by local minima
b
958 cm−1 / [917 + 873 + 851 cm−1]
c
Fitted Gaussian curves to the upper 2/3rds of ν1PO4 peak and determined FWHM of the Gaussian curve at 960 cm−1
d
Fitted one Lorentzian curve to ν1PO4 peak (baselined 920 to 990 cm−1) and determined FWHM and band position