HOLOGRAPHIC CHARACTERIZATION OF MICROBES

长期目标 描述一般有用的实时光散射方法 用于检测、鉴定和计数可移动的微生物。至 描述获取物种特定运动频谱的方法 水介质中微生物的“特征”。展示研究成果 可在自然界中就地鉴定单个微生物的设备 各种背景下的混合物，如碎屑 微粒和有机大分子。要开始构建一个 运动光谱签名和动态全息图的“库” 与影响我们的社会或我们的 环境，如沙门氏菌、大肠杆菌。为了展示这些 目前，这些技术是对流式细胞术等方法的补充 用于对单细胞微生物进行分类和研究。为…指明方向 使用类似的非侵入性技术 改善人类健康和福祉的情况。 实验设计 原型装置是从商业上可以买到的 激光多普勒测速仪。相干光的多普勒频移 可以检测到从活动微生物的运动部分散布的 通过光学外差技术。集合平均化 由此产生的光谱提高了信噪比，并给出了 微生物的“光谱”特征。同时，动态 全息图围绕激光节拍的轴线形成 样本。这些全息图包含所需的所有信息 对样品进行光学表征。例如，它是 理论上可以将一组动态全息图存储在 通过旋转晶体过程中的光学活性晶体介质 时间序列信息的接收。如果散射光 从第二个类似的微生物悬浮液中被用作输入 这个水晶店，参考光束将重建(和 容易检测的)在晶体旋转期间，在 通过与用于存储的弧相对应的弧线 签名原件。全息和光谱技术 是完全互补的。前者承诺快速光学 从包含以下内容的样本中处理签名和细胞计数 许多微生物，而后者承诺允许连续 微生物与颗粒物混合物的定量分析 饮用水、废水和 地下水。

Long-term Objectives To describe generally useful real-time light-scattering methods for detecting, identifying and counting motile microbes. To describe methods of obtaining species specific motion spectral "signatures" of microbes in aqueous media. To demonstrate research equipment which can identify individual microbes in situ in natural mixtures, against various backgrounds such as detrital microparticulate and organic macromolecules. To begin to build a "library" of the motion spectral signatures and dynamic holograms associated with motile microbes which impact our society or our environment, e.g., Salmonella, E. coli. To show how these techniques complement flow cytometry and other methods currently used to sort and study unicellular microbes. To point the way to using similar non-intrusive techniques in a wide variety of situations to improve human health and wellbeing. Experimental Design Prototype apparatus has been built from a commercially available Laser Doppler Velocimeter. The Doppler shifts of coherent light scattered from the moving parts of motile microbes can be detected by optical heterodyning techniques. Ensemble averaging of the resulting spectra enhances signal to noise ratios and gives "motion spectra" characteristic of the microbes. Simultaneously, dynamic holograms form around the axis of the laser beats exiting the sample. These holograms contain all the information require to optically characterize the sample. For example, it is theoretically possible to store a set of dynamic holograms in an optically active crystalline medium by rotating the crystal during reception of the time-series information. If the scattered light from a second similar suspension of microbes was used as input to this crystal store, the reference beam would reconstruct (and be readily detectable) during the rotation of the crystal, during passage through an arc corresponding to that used for storage of the original signature. Holographic and spectroscopic techniques are completely complementary. The former promises fast optical processing of signatures and cell count from samples containing many microbes, while the latter promises to allow continuous quantitative analysis of mixtures of microbes and particulate at very low concentration in drinking water, wastewater and groundwater.