Mass spectrometry imaging for biology and biotechnology

质谱分析是一种“宽带”技术——所有东西都有质量。质谱仪在过去的15年里发展起来，解决了越来越多的生物学问题，解决了样品的复杂性和生物分子领域的微妙之处。然而，直到最近，在以空间定义的方式从生物材料中获取质谱的能力方面才有了重大的发展——“质谱成像”。为这种应用设计的仪器可以生成图像，其中测量的信号不仅仅是颜色（如光学成像），而是质谱。我们建议在利物浦大学建立一个MS成像平台，供大学内外的其他科学家使用。该系统将把高分辨率、高灵敏度的质谱仪与两种不同的成像方式结合起来——一种是基质辅助激光解吸电离法（MALDI），另一种是激光激活电喷雾电离法（LAESI）。在MALDI中，样品被涂上一层基质分子，该基质分子吸收紫外线激光能量，并将该能量用于激活和电荷添加，从而从组织或样品中产生离子。在LAESI中，红外激光器用于在靠近探针的地方对样品进行局部加热和挥发，从而产生用于分析的离子。MALDI适用于生物小分子，而LAESI适用于生物大分子。这两种不同的来源允许分析从低分子量代谢物到大分子（如蛋白质）的整个生物分子范围。我们建议安装的质谱仪有几个优点。首先，它是一个高分辨率的仪器，精致的灵敏度通过离子光学的新设计得到增强，该设计将信息离子引导到质谱仪中，远离污染和背景-这大大提高了灵敏度。其次，该仪器包括一个离子迁移装置，该装置可以根据其横截面积进一步分解离子。这在成像应用中特别有利，因为样品的复杂性会影响信号对噪声的影响，从而影响灵敏度。传统上，该平台的主要应用是组织可视化——这里的范例项目是关节损伤的空间映射，或者与衰老生物学特别相关。虽然组织成像将是仪器时间的主要需求，但我们也将探索一种或其他电离方法的新应用。这些技术包括对已被阵列捕获的蛋白质或碳水化合物进行检测，对经过改造以产生新化学物质的微生物中的代谢物进行快速筛选，对生物液体中的蛋白质进行快速表型分析，以及对沉积在环境中的气味痕迹进行直接可视化。因此，新的能力将广泛适用于一大批bbsrc资助的项目。据我们所知，在英国没有类似的复杂和范围的系统，英国的研究人员可以公开使用。通过在利物浦建立这个平台，它将由利物浦大学技术理事会管理。技术司的任务是为大学内外的尽可能多的用户提供使用最好的研究设施的机会。它有机制和结构，以确保全职运作和确保使用，以及为适当开放的设施提供财政支持，并通过授予访问补助金，允许学者，特别是早期职业人员，能够在获得实质性资助之前使用这些设施。

Mass spectrometry is a 'broadband' technology - everything has a mass. Mass spectrometers have developed over the past 15 years to attack more and more problems in biology, addressing the issue of complexity of the sample and the subtleties of the biomolecular domain. However, it is only recently that there have been significant developments in the ability to acquire a mass spectrum from a biological material in a spatially defined fashion - 'MS imaging'. The instruments designed for this application can generate an image in which the measured signal is not simply a colour (as in optical imaging) but a mass spectrum. We propose to establish an MS imaging platform at the University of Liverpool that is accessible to other scientists within and outside the University. The system will couple a high resolution, high sensitivity mass spectrometer with two different imaging modalities - a matrix assisted laser desorption ionisation method (MALDI) and a laser activated electrospray ionisation method (LAESI). In MALDI, the sample is coated with a matrix molecule that absorbs the ultraviolet laser energy and which directs that energy to activation and charge addition to generate ions from the tissue or sample. In LAESI, an infrared laser is used to effect localised heating and volatilisation of the sample in close proximity to a probe that generates the ions for analysis. MALDI is preferred for small biomolecules, whereas LAESI is preferred for biological macromolecules. The two different sources permit the entire range of biological molecules, from low molecular weight metabolites to macromolecules such as proteins to be analysed.The mass spectrometer we propose to install has several advantages. First, it is a high resolution instrument and the exquisite sensitivity is enhanced by a new design within the ion optics that steers informative ions into the mass analyser and away from contamination and background - this greatly increases sensitivity. Secondly, the instrument includes an ion mobility device that can further resolve ions according to their cross sectional area. This is particularly advantageous in imaging applications, where the complexity of the sample can compromise signal to noise and thus, sensitivity.The main application for this platform has traditionally been in tissue visualisation - the exemplar project here is in the spatial mapping of damage to joints, or particular relevance to the biology of ageing. Whilst tissue imaging will be a major demand on instrument time, we will also explore new applications for one or the other ionisation methods. These include interrogation of proteins or carbohydrates that have been captured on arrays, rapid screening of metabolites in microorganisms that are engineered to generate new chemicals, for rapid phenotyping of proteins in biological fluids and for the direct visualisation of scent marks deposited in the environment. Thus, the new capacity will have broad applicability to a large set of BBSRC-funded projects.To our knowledge, there is no system of comparable sophistication and scope that is in the UK and openly available to UK researchers. By establishing this platform at Liverpool, it will be under the management of the University of Liverpool Technology Directorate. The Technology Directorate has the mission of providing access to the very best research facilities for the maximal number of users, both inside and outside the University. It has the mechanisms and structures to ensure full time operation and to ensure access, as well as providing financial support for properly open facilities such as this, and by awarding access grants to allow academics, and particularly early career staff, to be able to use such facilities in advance of winning substantive funding.