Holographic angular-domain elastic scattering

1402345贝格意义：这句耳熟能详的谚语，在人体内有着特殊的意义：许多大规模的变化都是由几个“早期反应”细胞触发的。例如过敏反应、伤口愈合和癌变。即使许多“相同”的细胞在实验室中暴露在相同的条件下，一些细胞的反应也会更快；这种差异是理解整个过程如何展开的线索，或许也是药物如何影响整个过程的线索。不幸的是，大多数测量细胞反应的方法都有以下局限性之一：(A)它们只计算许多细胞的平均值，(B)它们只测量每个细胞一次，或者(C)它们注入改变细胞功能的化学物质。在这个项目中，将建立一个没有这些限制的新的显微镜系统。只使用微弱的光线，许多单个细胞将被监测更长的一段时间，当它们对刺激做出反应时，产生细胞的化学和结构“历史”。这项测量技术将有助于识别早期反应细胞，并了解它们如何导致人体内的大规模行为。在一个令人感兴趣的特殊案例中，将研究一种称为“血小板脱颗粒”的细胞转化，因为它与HIV阳性个体神经疾病水平的增加有关。技术描述：该项目将一种新的生物光子学测量技术--全息角域弹性散射(HADES)应用于单个细胞对刺激的反应研究。角散射对细胞器的平均大小高度敏感，因此对细胞内容物的变化也非常敏感。全息术将使单细胞的第一性原理分析成为可能？第一次出现角散射。哈迪斯技术将在显微镜下与拉曼光谱相结合，拉曼光谱是一种提供化学特异性的补充技术。该仪器将获得单个细胞在经历变化时的形态和化学“历史”，例如(A)内皮细胞线粒体膜受损，(B)免疫细胞受到刺激，(B)血小板细胞经历脱颗粒，这是研究艾滋病毒相关神经认知障碍(HAND)的一个重要过程。这样的反应在不同的细胞之间可能会有很大的不同，这些差异可能是研究的重要参数。然而，许多分析方法并不提供单细胞数据，而且许多这样做的方法需要改变正在研究的过程的外源标记。因此，需要一种非标记、非破坏性的方法，这种方法可以重复地从单个细胞获得详细信息，而不会影响细胞功能或活性。HADES显微镜平台将提供丰富的信息，用于在逐个细胞的基础上表征细胞转化及其变异性。该奖项由两个项目联合颁发-(1)生物基础设施司(生物科学局)的生物研究仪器开发，(2)化学、生物工程、环境和运输系统司(工程局)的生物光子学。

1402345BergerSignificance:The familiar saying "every journey begins with a single step" has a special meaning in the human body: many large-scale changes are triggered by a few "early responder" cells. Examples include allergic reactions, wound healing, and cancerous transformations. Even when many "identical" cells are exposed to the same conditions in a laboratory, some respond faster; such differences are clues to understanding how an entire process unfolds, and perhaps how medicine can influence it. Unfortunately, most methods of measuring cellular responses have one of the following limitations: (a) they only calculate averages over many cells, (b) they measure each cell only once, or (c) they inject chemicals that alter the cells' function. In this project, a new microscope system will be built without these limitations. Using only low levels of light, many individual cells will be monitored for extended periods of time, producing chemical and structural "histories" of the cells as they respond to stimuli. This measurement technique will be useful for identifying early-responding cells and understanding how they lead to large-scale behavior in the human body. In a particular case of interest, a cellular transformation called "platelet degranulation" will be studied because it is associated with increased levels of neurological illness in HIV-positive individuals.Technical description:This project applies a new biophotonic measurement technique, holographic angular-domain elastic scattering (HADES), to studies of single cells responding to stimuli. Angular scattering is highly sensitive to the average size of organelles, and therefore to changes in cellular contents. Holography will enable first-principles analysis of single cells? angular scattering for the first time. The HADES technique will be combined in a microscope with Raman spectroscopy, a complementary technique that provides chemical specificity. This instrument will acquire morphological and chemical "histories" of single cells as they undergo changes, for example (a) endothelial cells receiving damage to their mitochondrial membranes, (b) immune cells being stimulated, and (b) platelet cells undergoing degranulation, a process of interest to research on HIV-associated neurocognitive disorder (HAND). Such reactions can vary greatly from one cell to the next, and these differences can be important parameters to study. Yet many analytical methods do not provide single-cell data, and many that do so require exogenous labels that alter the very process being studied. There is therefore a need for non-labeling, non-destructive methods that can obtain detailed information repeatedly from single cells, without affecting cellular function or viability. The HADES microscopy platform will provide rich information for characterizing cellular transformations and their variability on a cell-by-cell basis.This award is being made jointly by two Programs- (1) Instrument Development for Biological Research, in the Division of Biological Infrastructure (Biological Sciences Directorate), and (2) Biophotonics, in the Division of Chemical, Bioengineering, Environmental and Transport Systems (Engineering Directorate).