We have previously demonstrated native nano-desorption electrospray ionization (nano-DESI) mass spectrometry imaging of proteins and protein complexes in thin tissue section of rat kidney. Here, we demonstrate the integration of travelling wave ion mobility spectrometry (TWIMS) into the native nano-DESI MSI workflow. The benefits of TWIMS are twofold: Firstly, arrival time filtering allows subtraction of chemical noise and the resulting ion images show improved specificity. Secondly, the incorporation of TWIMS enables the calculation of collision cross sections, and thus a measure of protein structure, directly from the imaging dataset. Our results show good agreement between the collision cross sections determined from nano-DESI, which requires the use of a heated inlet, and those determined experimentally from liquid extraction surface analysis (LESA) with an ambient temperature inlet, and those available in the literature. Ion images and collision cross sections are presented for a range of proteins and protein assemblies with molecular weights of up to 42.6 kDa.

我们之前已经证明了大鼠肾脏薄组织切片中蛋白质和蛋白质复合物的天然纳米解吸电喷雾电离 (纳米 DESI) 质谱成像。在这里，我们展示了行波离子迁移谱 (TWIMS) 与原生 nano-DESI MSI 工作流程的集成。TWIMS 的好处有两个：首先，到达时间过滤允许减去化学噪声，所得离子图像显示出更高的特异性。其次，TWIMS 的结合可以直接从成像数据集中计算碰撞截面，从而测量蛋白质结构。我们的结果表明由纳米 DESI 确定的碰撞横截面之间具有良好的一致性，这需要使用加热入口，那些通过使用环境温度入口的液体萃取表面分析 (LESA) 实验确定的，以及文献中提供的那些。展示了一系列分子量高达 42.6 kDa 的蛋白质和蛋白质组装体的离子图像和碰撞截面。