Bennet Rachel V, Gamage Chaminda M, Fernández Facundo M
School of Chemistry and Biochemistry, Georgia Institute of Technology, USA.
J Vis Exp. 2013 Jul 12(77):e50575. doi: 10.3791/50575.
Mass spectrometry imaging (MSI) provides untargeted molecular information with the highest specificity and spatial resolution for investigating biological tissues at the hundreds to tens of microns scale. When performed under ambient conditions, sample pre-treatment becomes unnecessary, thus simplifying the protocol while maintaining the high quality of information obtained. Desorption electrospray ionization (DESI) is a spray-based ambient MSI technique that allows for the direct sampling of surfaces in the open air, even in vivo. When used with a software-controlled sample stage, the sample is rastered underneath the DESI ionization probe, and through the time domain, m/z information is correlated with the chemical species' spatial distribution. The fidelity of the DESI-MSI output depends on the source orientation and positioning with respect to the sample surface and mass spectrometer inlet. Herein, we review how to prepare tissue sections for DESI imaging and additional experimental conditions that directly affect image quality. Specifically, we describe the protocol for the imaging of rat brain tissue sections by DESI-MSI.
质谱成像（MSI）可提供非靶向分子信息，具有最高的特异性和空间分辨率，用于在数百至数十微米尺度上研究生物组织。在环境条件下进行时，无需样品预处理，从而简化了实验方案，同时保持所获信息的高质量。解吸电喷雾电离（DESI）是一种基于喷雾的环境MSI技术，可在露天甚至体内直接对表面进行采样。当与软件控制的样品台一起使用时，样品在DESI电离探头下方进行光栅扫描，通过时域，m/z信息与化学物质的空间分布相关联。DESI-MSI输出的保真度取决于源相对于样品表面和质谱仪入口的方向和定位。在此，我们综述了如何为DESI成像制备组织切片以及直接影响图像质量的其他实验条件。具体而言，我们描述了通过DESI-MSI对大鼠脑组织切片进行成像的实验方案。
