Raman imaging of materials in the natural environment

绝大多数关于生物体对环境变化的化学反应的研究是在受控的实验室条件下对模式物种和系统进行的。关于生活在自然环境中的物种的研究相对较少，从同质条件下收集的洞察在多大程度上反映了复杂环境中的运作过程，目前尚不清楚。填补这一空白需要实验室级别的设备，这些设备可以部署在实地，在复杂和动态的环境背景下可靠地捕捉生物多样性和生态过程的全部情况。拉曼成像光谱学在样品表面提供异常高分辨率、空间清晰的化学信息。例如，这种方法已被用于植物科学，以揭示新的机制，例如植物生产稀有矿物。然而，到目前为止，共焦成像拉曼能力一直局限于实验室使用。雷尼绍英国公司最近开发了第一个便携式共聚焦成像拉曼光谱系统，该系统首次可用于以尽可能高的空间和光谱精度绘制野外样品的化学图谱。这项新技术将使研究人员能够以前所未有的规模在现场测量化学结构和跟踪过程；这一新能力有望揭示迄今隐藏的生态成分和过程。要实现这一潜力，首先需要将基于现场的仪器(Virsa)与基于实验室的同类系统(INVIA)进行校准。这些雷尼绍成像拉曼系统提供了独特的功能，使其特别适合分析环境样品：LiveTrack聚焦允许在粗糙的表面上进行化学映射，而无需更改或样品准备；超快探测器能够在最短时间内测量大片样品区域；探测器还具有高灵敏度，使其能够捕获异质样品中的低浓度分子，甚至在光学噪声环境中；它以化合物为目标进行测量的能力进一步减少了分析时间，这使得重复性远远超过标准化学分析方法的可行程度。与所有的拉曼系统一样，它们能够捕捉活组织中的有机和无机分子，因为这种方法对水不敏感(与红外光谱不同)。INVIA和VIRSA系统结合在一起，提供了新的能力，这将使从环境样品中获得的化学和结构信息的类型、精度和数量发生阶段性变化。我们将利用这一能力回答有关植物-土壤反馈、土壤微生物过程和有机体对压力的反应等紧迫问题。在每个项目中，我们将根据INVIA的测量结果校准VISA值，以便为在现场研究中广泛采用拉曼共焦成像奠定基础。我们将通过多种途径(培训、出版、合作)来扩大人们对这种新型设备在国家环境研究中心范围内提供环境研究能力的认识。

The vast majority of research on chemical responses by organisms to environmental change are conducted on model species and systems within controlled laboratory conditions. There are comparatively fewer studies on species living in the natural environment and it remains unclear how well insights gleaned from homogeneous conditions reflect processes operating in complex environments. Filling this gap requires laboratory-grade equipment that can be deployed in the field to reliably capture the full breadth of biodiversity and ecological processes within their complex and dynamic environmental context. Raman imaging spectroscopy provides exceptionally high-resolution, spatially explicit chemical information across a sample surface. The method has been used in plant sciences, for example, to uncover novel mechanisms, e.g. plant production of rare minerals. However, until now, confocal imaging Raman capability has been limited to laboratory use. Renishaw UK recently developed the first portable, confocal imaging Raman spectroscopy system, which - for the first time - can be used to map the chemistry of samples in the field with the highest possible spatial and spectral precision. This new technology will enable researchers to measure chemical structure and track processes in situ at a scale previously impossible; this new capability promises to shed light on heretofore hidden ecological components and processes. Fulfilling this potential firstly requires calibration of the field-based instrument (the Virsa) against a comparable laboratory-based system (the inVia).These Renishaw imaging Raman systems offer unique capability that makes them particularly well-suited for analysing environmental samples: LiveTrack focusing allows for chemical mapping over a rough surface without alteration or sample preparation; the ultra-fast detector enables large sample areas to be measured in minimal time; the detector is also highly sensitive which allows it to capture low concentration molecules within a heterogenous sample and even within an optically noisy environment; and its ability to target compounds for measurement further reduces analysis time, which allows for far greater replication than is feasible with standard chemical analysis methods. As with all Raman systems, they are able to capture both organic and inorganic molecules in living tissues because the method is insensitive to water (unlike infrared spectroscopy). Together, the inVia and Virsa systems offer novel capability that will create a step change in the type, precision and amount of chemical and structural information that can be obtained from environmental samples. We will take advantage of this capability to answer pressing questions about plant-soil feedbacks, soil microbial processes and organismal responses to stress. Within each project, we will calibrate the Virsa against measurements taken by the inVia in order to set the foundation for widespread adoption of Raman confocal imaging in field research. We will use a number of routes (training, publication, collaborations) to broaden awareness of the capability this novel equipment offers environmental research across the NERC remit.