Matrix/mineral ratio and domain size variation with bone tissue age: A photothermal infrared study
Matrix/mineral ratio and domain size variation with bone tissue age: A photothermal infrared study
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DOI：
10.1016/j.jsb.2022.107878
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发表时间：
2022-07-11
影响因子：
3
通讯作者：
Holl, Mark M. Banaszak
中科院分区：
文献类型：
--
作者：
Ahn, Taeyong;Jueckstock, Max;Holl, Mark M. Banaszak
原子力显微镜-红外光谱 (AFM-IR) 和光学光热红外光谱 (OPTIR) 的光谱成像空间分辨率分别低至 - 50 nm 和 - 500 nm，用于表征骨中纳米至微米级的化学成分变化。由于已知这些变化与年龄有关，因此采用了荧光标记的骨样本。通过 AFM-IR 和 O-PTIR 测量，平均基质/矿物质比值随着骨组织的成熟而降低，这与之前发表的 FTIR 和拉曼光谱结果一致。 AFM-IR 获得的 IR 比率图揭示了与骨表面平行的基质/矿物质比率生成微米级带的变化，以及这些带内尺寸范围为 50 至 700 nm 的较小域，这与之前发布的纳米机械异质性的长度尺度一致。基质/矿物质的变化并不随组织年龄呈现平滑梯度。相反，基质/矿物转变在 100-200 nm 的长度范围内急剧发生。 O-PTIR 还揭示了与骨表面平行的基质/矿物质带域，导致从最年轻的组织到最成熟的组织的基质/矿物质比率波动。与较老的组织相比，AFM-IR 和 O-PTIR 都显示年轻组织的基质/矿物质比值变化更大。这些数据共同证实了 O-PTIR 和 AFM-IR 是可视化批量光谱数据的技术，与拉曼和 FTIR 等高阶成像技术一致，同时揭示了矿化模式如何随骨组织年龄变化的新见解。
Atomic force microscopy-infrared spectroscopy (AFM-IR) and optical photothermal infrared spectroscopy (OPTIR), which feature spectroscopic imaging spatial resolution down to - 50 nm and - 500 nm, respectively, were employed to characterize the nano- to microscale chemical compositional changes in bone. Since these changes are known to be age dependent, fluorescently labelled bone samples were employed. The average matrix/mineral ratio values decrease as the bone tissue matures as measured by both AFM-IR and O-PTIR, which agrees with previously published FTIR and Raman spectroscopy results. IR ratio maps obtained by AFM-IR reveal variation in matrix/mineral ratio-generating micron-scale bands running parallel to the bone surface as well as smaller domains within these bands ranging from - 50 to 700 nm in size, which is consistent with the previously published length scale of nanomechanical heterogeneity. The matrix/mineral changes do not exhibit a smooth gradient with tissue age. Rather, the matrix/mineral transition occurs sharply within the length scale of 100-200 nm. O-PTIR also reveals matrix/mineral band domains running parallel to the bone surface, resulting in waves of matrix/mineral ratios progressing from the youngest to most mature tissue. Both AFM-IR and O-PTIR show a greater variation in matrix/mineral ratio value for younger tissue as compared to older tissue. Together, this data confirms O-PTIR and AFM-IR as techniques that visualize bulk spectroscopic data consistent with higher-order imaging techniques such as Raman and FTIR, while revealing novel insight into how mineralization patterns vary as bone tissue ages.