DEVELOPMENT OF FAR INFRARED MICROSPECTROSCOPY AT BEAMLINE U2B

保存骨组织样本的标准方法是包埋 它们在石蜡或塑料（甲基丙烯酸甲酯/邻苯二甲酸二丁酯）中。 那么他们可以在5-10节？m传输厚度 红外实验 需要这些薄切片是因为 磷酸盐和蛋白质提供的极大信号 对红外光谱的贡献。 虽然嵌入提供了 这是一种检查骨骼矿物质成分的极好方法， 该技术具有几个缺点，包括（1）干扰 包埋介质的红外吸收，以及（2）不确定 包埋过程是否影响蛋白质二级结构。 常规的冷冻/切片机切割方法可用于提供 原生 组织样本 但是，很难节到少 比20？m，这是有问题的，由于高红外吸收 在这些厚度。 因此，我们使用衰减全反射 红外显微光谱法来检查这样的天然样品（例如， 塑料）。 将组织切片冷冻并用 切片并使用衰减全反射（ATR）检查。 ATR 是一种表面技术， 十个？m进入表面的基础上的倏逝波阵面 红外辐射 由于这种性质， 湿. ATR显微红外光谱法是一种上级方法， 检查蛋白质光谱，因为没有变性条件， 蛋白质结构的改变是必需的。

A standard method for preserving bone tissue samples is to embed them in paraffin or plastic (methyl methacrylate/dibutyl phthalate). Then they can be sectioned at 5-10 ?m thicknesses for transmission infrared experiments. These thin sections are required due to the extremely large signals provided by the phosphate and protein contributions to the infrared spectra. Although embedding provides an excellent means for examining the mineral components of bone, this technique has a few drawbacks including (1) interference of the infrared absorbance of the embedding medium, and (2) it is uncertain whether the embedding process affects protein secondary structure. Conventional freeze/microtome cleavage methods can be used to provide native tissue samples. However, it is difficult to section to less than 20 ?m, which is problematic due to the high infrared absorbance at those thicknesses. Thus, we are using attenuated total reflection infrared microspectroscopy to examine such native samples (eg. without plastic). Sections of tissue are frozen and cleaved with a microtome and examined using Attenuated Total Reflectance (ATR). ATR is a surface technique that probes the tissue structure approximately 10 ?m into the surface based on the evanescent wavefront of the infrared radiation. Due to this property, the samples are examined wet. ATR infrared microspectroscopy is a superior method for examining protein spectra, since no denaturing conditions that may perturb the protein structure are required.