Laser-based high-resolution mass spectrometry imaging at ambient conditions has promising applications in life science. However, the ion yield during laser desorption/ablation is poor. Here, transmission atmospheric pressure laser desorption ionization combined with a compact postphotoionization (t-AP-LDI/PI) assembly with a krypton discharge lamp was developed for the untargeted imaging of various biomolecules. The spatial distributions of numerous lipid classes, fatty acids, neurotransmitters, and amino acids in the subregions of mouse cerebellum tissue were obtained. Compared with single laser ablation, the sensitivities for most analytes were increased by 1 to 3 orders of magnitude by dopant-assisted postphotoionization. After careful optimization, a spatial resolution of 4 μm could be achieved for the metabolites in mouse hippocampus tissue. Finally, the melanoma tissue slices were analyzed using t-AP-LDI/PI MSI, which revealed the metabolic heterogeneity of the melanoma microenvironment and exhibited the phenomenon of abnormal proliferation and invasion trends in tumor cells.

中文翻译：

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透射常压激光解吸电离/后光电离质谱成像的发展

环境条件下基于激光的高分辨率质谱成像在生命科学中具有广阔的应用前景。然而，激光解吸/烧蚀期间的离子产率较差。这里，开发了传输大气压激光解吸电离与带有氪放电灯的紧凑型后光电离（t-AP-LDI/PI）组件的结合，用于各种生物分子的非靶向成像。获得了小鼠小脑组织亚区域中多种脂质类别、脂肪酸、神经递质和氨基酸的空间分布。与单次激光烧蚀相比，掺杂剂辅助后光电离对大多数分析物的灵敏度提高了 1 至 3 个数量级。经过仔细优化，小鼠海马组织代谢物的空间分辨率可以达到4μm。最后，利用t-AP-LDI/PI MSI对黑色素瘤组织切片进行分析，揭示了黑色素瘤微环境的代谢异质性，并表现出肿瘤细胞异常增殖和侵袭趋势的现象。