HOLOGRAPHIC CHARACTERIZATION OF MICROBES

长期目标 描述通常有用的实时光散射方法 用于检测、识别和计数能动微生物。 到 描述获得物种特异性运动光谱的方法 水介质中微生物的“特征”。 为了证明研究 一种可以在自然环境中原位识别单个微生物的设备， 混合物，对各种背景，如碎屑 微粒和有机大分子。 要开始建立一个 运动光谱特征和动态全息图“库” 与影响我们的社会或我们的 环境，例如，沙门氏菌属、E.杆菌 为了展示这些 技术补充了流式细胞术和目前的其它方法 用于分类和研究单细胞微生物。 为…指明道路 使用类似的非侵入性技术， 改善人类健康和福祉。 实验设计 原型装置已经由市售的 激光多普勒测速仪。 相干光的多普勒频移 从活动微生物的运动部分散射的光可以被检测到 通过光学外差技术。 对 得到的光谱增强了信噪比， 光谱”的微生物的特征。 同时，动态 全息图围绕离开激光器的激光拍的轴形成， sample. 这些全息图包含了 光学表征样品。 例如， 理论上可以将一组动态全息图存储在 光学活性晶体介质， 时间序列信息的接收。 如果散射光 来自第二种类似的微生物悬浮液的微生物用作输入， 在该晶体存储器中，参考光束将重构（并且 在晶体旋转期间， 穿过与用于储存 原始签名。 全息和光谱技术 是完全互补的。 前者承诺快速光学 处理来自样本的特征和细胞计数， 许多微生物，而后者承诺允许连续 微生物和颗粒物混合物的定量分析. 饮用水、废水和废水中的浓度极低， 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.