Mass spectrometry imaging for biology and biotechnology

质谱学是一种“宽带”技术--任何东西都有质量。在过去的15年里，质谱仪已经发展起来，以解决越来越多的生物学问题，解决样品的复杂性和生物分子领域的微妙问题。然而，直到最近，才在以空间定义的方式从生物材料获得质谱图的能力方面有了重大发展--‘MS成像’。为这一应用设计的仪器可以生成图像，其中测量的信号不是简单的颜色(如光学成像)，而是质谱图。我们建议在利物浦大学建立一个MS成像平台，大学内外的其他科学家都可以访问。该系统将把一个高分辨率、高灵敏度的质谱仪与两种不同的成像方式相结合--基质辅助激光解吸电离法(MALDI)和激光激活电喷雾电离法(LAESI)。在MALDI中，样品被一种基质分子覆盖，该基质分子吸收紫外线激光能量，并将能量引导到激活和电荷加成，以从组织或样品中产生离子。在LAESI中，红外激光被用来在靠近探测器的地方对样品进行局部加热和挥发，探测器产生用于分析的离子。MALDI是生物小分子的首选，而LAESI是生物大分子的首选。这两种不同的来源可以分析从低分子代谢物到蛋白质等大分子的所有生物分子。我们建议安装的质谱仪有几个优点。首先，它是一种高分辨率仪器，通过离子光学中的新设计增强了精致的灵敏度，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率装置，可以根据离子的横截面积进一步分解离子。这在成像应用中尤其有利，在成像应用中，样本的复杂性可能会影响信噪比，从而影响灵敏度。该平台的主要应用传统上是组织可视化-这里的样本项目是关节损伤的空间映射，或与衰老生物学特别相关的空间映射。虽然组织成像将是仪器时间的主要需求，但我们也将探索其中一种电离方法的新应用。这些包括对阵列捕获的蛋白质或碳水化合物的询问，对微生物中产生新化学物质的代谢物的快速筛选，对生物液中蛋白质的快速表型分析，以及对环境中沉积的气味标记的直接可视化。因此，新的能力将对BBSRC资助的大量项目具有广泛的适用性。据我们所知，英国没有任何系统具有类似的复杂性和范围，并向英国研究人员开放。通过在利物浦建立这个平台，它将由利物浦大学技术委员会管理。技术局的任务是为大学内外最多的用户提供使用最好的研究设施的机会。它有机制和结构来确保全职运作和使用，并为像这样的适当开放的设施提供财政支持，并通过发放准入赠款，使学者，特别是早期职业工作人员能够在赢得实质性资金之前使用这些设施。

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.