MICRODIFFRACTION DEVELOPMENT & MICRODIFFRACTION STUDIES OF CARTILAGE & COLLAGEN

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。已建议在当前的NIH赠款周期内开发BioCAT的微探测器能力。BioCAT设施的一个推力区域是来自复杂生物材料的静态和时间分辨光纤衍射测量。这些区域之一是肌腱、软骨和皮肤中较小有序区域内的胶原纤维结构。在这里，我们报告了初步的显微衍射实验，证明了这种研究18ID的可行性。一个KB镜像系统(XRadia Inc.)被用来产生距最后一个反射镜300 mm的6x6um^2聚焦光束，并将入射光束准直到100x100微米以减小发散。该系统与来自我们的Si(111)单色仪的12keV单色束对准。在样品位置(距离第二个KB镜20厘米)获得的光束尺寸为6×6微米半高宽。这些样品用低温冷冻机保存，以防止辐射损伤。我们能够分辨出鼠尾胶原(I型)和软骨组织(II型)的紧密间隔(1/67 mm)的胶原子午线反射。我们预计，这一装置将成为研究多种结缔组织类型的胶原基结构的通用工具，并为研究薄组织标本中的其他局部有序结构(如淀粉样聚集体)开辟了可能性。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The development of BioCAT's microprobe capabilities has been proposed for the current NIH grant cycle. A thrust area at the BioCAT facility is static and time-resolved fiber-diffraction measurements from complex biological materials. One of these areas is the structure of collagenous fibers within small ordered regions in tendons, cartilage, and skin. Here we report on preliminary microdiffraction experiments demonstrating the feasibility of such studies on 18ID. A KB mirror system (Xradia Inc.) was used to produce a 6x6 um^2 focused beam, 300 mm from the last mirror, and the incident beam was collimated to 100x100 microns to reduce the divergence. The system was aligned to a 12 keV monochromatic beam from our Si(111) monochromator. The beam size obtained was 6 x 6 micron FWHM at the sample position (20 cm from the second KB mirror). The samples were kept at low temperature using a cryostream to prevent radiation damage. We were able to resolve the closely spaced (1/67 mm) collagen meridional reflections from rat-tail collagen (type I) and from cartilage tissue (type II). We anticipate that this setup will be a versatile tool for studying collagen-based structures in a number of connective tissue types, as well as open up the possibility of studying other locally ordered structures (e.g. Amyloid aggregates) in thin tissue specimens.