Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, 14853, USA.
Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, 14853, USA.
Calcif Tissue Int. 2021 Jul;109(1):77-91. doi: 10.1007/s00223-021-00825-4. Epub 2021 Mar 12.
Bone mineral carbonate content assessed by vibrational spectroscopy relates to fracture incidence, and mineral maturity/ crystallinity (MMC) relates to tissue age. As FT-IR and Raman spectroscopy become more widely used to characterize the chemical composition of bone in pre-clinical and translational studies, their bone mineral outcomes require improved validation to inform interpretation of spectroscopic data. In this study, our objectives were (1) to relate Raman and FT-IR carbonate:phosphate ratios calculated through direct integration of peaks to gold-standard analytical measures of carbonate content and underlying subband ratios; (2) to relate Raman and FT-IR MMC measures to gold-standard analytical measures of crystal size in chemical standards and native bone powders. Raman and FT-IR direct integration carbonate:phosphate ratios increased with carbonate content (Raman: p < 0.01, R = 0.87; FT-IR: p < 0.01, R = 0.96) and Raman was more sensitive to carbonate content than the FT-IR (Raman slope + 95% vs FT-IR slope, p < 0.01). MMC increased with crystal size for both Raman and FT-IR (Raman: p < 0.01, R = 0.76; FT-IR p < 0.01, R = 0.73) and FT-IR was more sensitive to crystal size than Raman (c-axis length: slope FT-IR MMC + 111% vs Raman MMC, p < 0.01). Additionally, FT-IR but not Raman spectroscopy detected differences in the relationship between MMC and crystal size of carbonated hydroxyapatite (CHA) vs poorly crystalline hydroxyapatites (HA) (slope CHA + 87% vs HA, p < 0.01). Combined, these results contribute to the ability of future studies to elucidate the relationships between carbonate content and fracture and provide insight to the strengths and limitations of FT-IR and Raman spectroscopy of native bone mineral.
通过振动光谱评估的骨矿物质碳酸盐含量与骨折发生率有关，而矿物质成熟度/结晶度（MMC）与组织年龄有关。随着傅里叶变换红外（FT-IR）和拉曼（Raman）光谱在临床前和转化研究中越来越多地用于描述骨的化学成分，其骨矿物质研究结果需要改进验证，以告知对光谱数据的解释。在这项研究中，我们的目标是：（1）通过直接积分峰来计算 Raman 和 FT-IR 的碳酸盐：磷酸盐比值，以与碳酸盐含量的金标准分析测量值和基础亚带比值相关联；（2）将 Raman 和 FT-IR 的 MMC 测量值与化学标准品和天然骨粉中金标准分析的晶体尺寸相关联。Raman 和 FT-IR 直接积分的碳酸盐：磷酸盐比值随碳酸盐含量增加而增加（Raman：p<0.01，R=0.87；FT-IR：p<0.01，R=0.96），并且 Raman 比 FT-IR 对碳酸盐含量更敏感（Raman 斜率+95%vs FT-IR 斜率，p<0.01）。对于 Raman 和 FT-IR，MMC 随晶体尺寸增加而增加（Raman：p<0.01，R=0.76；FT-IR：p<0.01，R=0.73），并且 FT-IR 比 Raman 对晶体尺寸更敏感（c 轴长度：FT-IR MMC 斜率+111%vs Raman MMC，p<0.01）。此外，FT-IR 而不是 Raman 光谱检测到 MMC 与碳酸化羟磷灰石（CHA）和非晶羟磷灰石（HA）的晶体尺寸之间关系的差异（斜率 CHA+87%vs HA，p<0.01）。综上所述，这些结果有助于未来研究阐明碳酸盐含量与骨折之间的关系，并为 FT-IR 和 Raman 光谱分析天然骨矿物质的优势和局限性提供了深入的了解。
