Franck Julien, Arafah Karim, Barnes Alan, Wisztorski Maxence, Salzet Michel, Fournier Isabelle
Université de Lille1, CNRS, Team, Laboratoire de Neuroimmunologie des Annelides, MALDI Imaging, F-59655 Villeneuve d'Ascq Cedex, France.
Anal Chem. 2009 Oct 1;81(19):8193-202. doi: 10.1021/ac901328p.
Nowadays, matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) is a powerful technique to obtain the distribution of endogenous and exogenous molecules within tissue sections. It can, thus, be used to study the evolution of molecules across different physiological stages in order to find out markers or get knowledge on signaling pathways. In order to provide valuable information, we must carefully control the sample preparation to avoid any delocalization of molecules of interest inside the tissue during this step. Currently, two strategies can be used to deposit chemicals, such as the MALDI matrix, onto the tissue both involving generation of microdroplets that will be dropped off onto the surface. First strategy involves microspraying of solutions. Here, we have been interested in the development of a microspotting strategy, where nanodroplets of solvent are ejected by a piezoelectric device to generate microspots at the tissue level. Such systems allow one to precisely control sample preparation by creating an array of spots. In terms of matrix crystallization, a microspotting MALDI matrix is hardly compatible with the results by classical (pipetting) methods. We have thus synthesized and studied new solid ionic matrixes in order to obtain high analytical performance using such a deposition system. These developments have enabled optimization of the preparation time because of the high stability of the printing that is generated in these conditions. We have also studied microspotting for performing on-tissue digestion in order to go for identification of proteins or to work from formalin fixed and paraffin embedded (FFPE) tissue samples. We have shown that microspotting is an interesting approach for on tissue digestion. Peptides, proteins, and lipids were studied under this specific preparation strategy to improve imaging performances for this class of molecules.
如今，基质辅助激光解吸电离质谱成像（MALDI MSI）是一种用于获取组织切片内源性和外源性分子分布的强大技术。因此，它可用于研究分子在不同生理阶段的演变，以找出标志物或了解信号通路。为了提供有价值的信息，我们必须仔细控制样品制备过程，以避免在此步骤中感兴趣的分子在组织内发生任何离位。目前，有两种策略可用于将化学物质（如MALDI基质）沉积到组织上，这两种策略都涉及产生微滴并将其滴落在表面上。第一种策略涉及溶液的微喷雾。在这里，我们一直致力于开发一种微点样策略，即通过压电装置喷射溶剂纳米滴以在组织水平上产生微点。这种系统允许通过创建点阵列来精确控制样品制备。就基质结晶而言，微点样MALDI基质与传统（移液）方法的结果几乎不兼容。因此，我们合成并研究了新的固体离子基质，以便使用这种沉积系统获得高分析性能。由于在这些条件下产生的打印具有高稳定性，这些进展使得制备时间得以优化。我们还研究了用于进行组织上消化的微点样，以便鉴定蛋白质或处理福尔马林固定石蜡包埋（FFPE）组织样品。我们已经表明，微点样是一种用于组织上消化的有趣方法。在这种特定的制备策略下研究了肽、蛋白质和脂质，以改善这类分子的成像性能。
