Sensitivity of the amide I band to matrix manipulation in bone: a Raman micro-spectroscopy and spatially offset Raman spectroscopy study.
Sensitivity of the amide I band to matrix manipulation in bone: a Raman micro-spectroscopy and spatially offset Raman spectroscopy study.
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酰胺 I 带对骨基质操作的敏感性：拉曼显微光谱和空间偏移拉曼光谱研究。
DOI：
10.1039/d3an00527e
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Nyman,JeffryS
中科院分区：
文献类型：
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作者：
Ahmed,Rafay;Unal,Mustafa;Gautam,Rekha;Uppuganti,Sasidhar;Derasari,Shrey;Mahadevan-Jansen,Anita;Nyman,JeffryS
骨的抗断裂性源于矿物质、胶原原纤维（即，α1和α2胶原蛋白I链的交联三螺旋）、非胶原蛋白和水。拉曼光谱（RS）不仅对这些组分的相对分数敏感，而且对骨蛋白的二级结构也敏感。为了评估RS检测蛋白质结构差异的能力，我们量化了在100 °C下连续高压灭菌（AC）人皮质骨的效果，（34.47 kPa），然后在120 °C使用商用拉曼显微光谱（μRS）仪器和自定义空间偏移RS（SORS），在酰胺I波段上测量（± 117.21 kPa）一种仪器，在该仪器中，收集光纤环偏离手持式圆柱形探头内的中心激发光纤。在临床上可行的情况下，通过SORS的测量涉及通过组织模拟物的层收集尸体股骨中段（5名男性和5名女性供体）的拉曼光谱。否则，直接从每个骨骼获取μRS和SORS测量值。使用酰胺I亚峰比（强度I，在λ 1670 cm−1处相对于λ 1610 cm−1和λ 1640 cm−1处的强度）评估胶原I螺旋状态的AC相关变化。高压灭菌操作显著降低了选定的酰胺I亚峰比率，并使μRS和SORS中的Δ 1605 cm−1（μRS）、Δ 1636 cm−1（SORS）和Δ 1667 cm−1处的峰发生位移。与μRS相比，当光纤探针直接应用于骨时，SORS检测到酰胺I亚峰比率的更显著差异。SORS还检测到I1670/I1610和I1670/I1640的AC相关降低，当通过7 mm偏心距环（但不是5 mm或6 mm偏心距环）的厚度≤2 mm的组织模拟物层采集光谱时。总的来说，SORS仪器比传统μRS仪器对影响骨抗断裂性的有机基质中的压力和温度相关变化更敏感，但酰胺I带的SORS分析仅限于2 mm厚的覆盖层。
The fracture resistance of bone arises from the hierarchical arrangement of minerals, collagen fibrils (i.e., cross-linked triple helices of α1 and α2 collagen I chains), non-collagenous proteins, and water. Raman spectroscopy (RS) is not only sensitive to the relative fractions of these constituents, but also to the secondary structure of bone proteins. To assess the ability of RS to detect differences in the protein structure, we quantified the effect of sequentially autoclaving (AC) human cortical bone at 100 °C (∼34.47 kPa) and then at 120 °C (∼117.21 kPa) on the amide I band using a commercial Raman micro-spectroscopy (μRS) instrument and custom spatially offset RS (SORS) instrument in which rings of collection fiber optics are offset from the central excitation fiber optics within a hand-held, cylindrical probe. Being clinically viable, measurements by SORS involved collecting Raman spectra of cadaveric femur mid-shafts (5 male & 5 female donors) through layers of a tissue mimic. Otherwise, μRS and SORS measurements were acquired directly from each bone. AC-related changes in the helical status of collagen I were assessed using amide I sub-peak ratios (intensity, I, at ∼1670 cm−1 relative to intensities at ∼1610 cm−1 and ∼1640 cm−1). The autoclaving manipulation significantly decreased the selected amide I sub-peak ratios as well as shifted peaks at ∼1605 cm−1 (μRS), ∼1636 cm−1 (SORS) and ∼1667 cm−1 in both μRS and SORS. Compared to μRS, SORS detected more significant differences in the amide I sub-peak ratios when the fiber optic probe was directly applied to bone. SORS also detected AC-related decreases in I1670/I1610 and I1670/I1640 when spectra were acquired through layers of the tissue mimic with a thickness ≤2 mm by the 7 mm offset ring, but not with the 5 mm or 6 mm offset ring. Overall, the SORS instrument was more sensitive than the conventional μRS instrument to pressure- and temperature-related changes in the organic matrix that affect the fracture resistance of bone, but SORS analysis of the amide I band is limited to an overlying thickness layer of 2 mm.