The structure of content: phase contrast in a microprobe

描述（由申请人提供）：细胞的许多关键功能取决于金属的催化特性，然而，如果金属以异常高浓度（或不正确调节）存在，许多这些相同的金属可能具有极大的毒性，或导致衰弱性疾病。铜和锌是抗氧化蛋白Cu/Zn超氧化物歧化酶的组成部分，这种酶在细胞衰老过程中被认为存在，并且以突变形式与神经退行性疾病（如肌萎缩性侧索硬化症或卢伽雷氏病）有关。顺铂是一种众所周知的癌症治疗药物，但其对细胞特定区域的亲和力尚不完全清楚。硬x射线微探针在检测和定量生物样品中的痕量金属浓度方面表现出色，但目前还不能通过成像超微结构来将金属置于正确的细胞环境中，也不能确定样品质量以提供真正的痕量金属浓度定量信息。我们希望在硬x射线微探针中实现定量相衬成像来解决这个问题。我们将开发一种优化的分段探测器，用于差分相对比成像，该探测器将被纳入美国阿贡国家实验室先进光子源的带板微探针的常规使用，这是美国最重要的硬x射线同步光源。我们将开发方法和软件，用于使用新探测器获得的数据进行定量相对比分析。虽然我们已经展示了软x射线显微镜中定量相衬图像的几个例子，但我们现在希望开发软件，使APS微探针的用户可以常规使用这种分析方法。我们的目标是让精通生物医学研究（但不包括x射线光学和分析方法）的用户能够以用户友好的方式利用免费软件的这一功能。然后，我们希望证明该系统能够定量样品质量，并同时观察细胞中亚100纳米结构，同时绘制痕量元素分布。第三代存储环的x射线微探针代表了数百万美元的投资。能够真正量化元素浓度，而不仅仅是元素含量，并将其与细胞超微结构联系起来，是迫切需要的，正如在nih支持的研究中使用x射线微探针的独立研究人员的支持信所表明的那样。

DESCRIPTION (provided by applicant): Numerous key functions of cells hinge upon the catalytic properties of metals, yet if metals are present in abnormally high concentrations (or incorrectly regulated) many of these same metals can be extremely toxic, or lead to debilitating diseases. Copper and zinc are components of the anti-oxidant protein Cu/Zn superoxide dismutase, which has been implied in cellular aging and in mutant forms has been linked to neurodegenerative diseases such as amytrophic lateral sclerosis (ALS, or Lou Gehrig's disease). Cisplatin is a well-known drug for cancer therapy but its affinity for specific regions in a cell is imperfectly understood. Hard X-ray microprobes excel at detecting and quantifying trace metal concentrations in biological samples, but at present they cannot image ultrastructure to place the metals in their correct cellular context, or determine the specimen mass so as to deliver truly quantitative information on trace metal concentration. We wish to implement quantitative phase contrast imaging in a hard x-ray microprobe to address this problem. We will develop an optimized segmented detector for differential phase contrast imaging that will be incorporated into routine use in a zone plate based microprobe at the Advanced Photon Source at Argonne National Laboratory, the premier hard x-ray synchroton light source in the U.S. We will develop methodology and software for quantitative phase contrast analysis using data obtained with the new detector. While we have demonstrated a few examples of quantitative phase contrast images in soft x-ray microscopy, we now wish to develop software to make this analysis approach routinely available to users of the APS microprobe. Our goal is to allow users expert in their biomedical studies (but not in x-ray optics and analysis methods) to exploit this capability with freely-available software in a user friendly fashion. We then wish to demonstrate the ability of the system to quantify specimen mass and observe sub-100 nm structure in cells simultaneously with mapping trace elemental distributions. X-ray microprobes at third generation storage rings represent a multimillion dollar investment. The ability to truly quantify element concentrations instead of just elemental content, and to correlate this to cellular ultrastructure, is keenly desired as indicated by letters of support from independent investigators who use X-ray microprobes for their NIH-supported studies.