posted on 2024-03-12, 18:34authored byZhibin Bao, Dian Yu, Jinxiang Fu, Jianchi Gu, Jia Xu, Liang Qin, Hao Hu, Chenyu Yang, Wenjuan Liu, Lulu Chen, Ran Wu, Haiqiang Liu, Hualei Xu, Hua Guo, Lei Wang, Yijun Zhou, Qi Li, Xiaodong Wang
Matrix-assisted laser desorption/ionization mass spectrometry
imaging
(MALDI-MSI), which is a label-free imaging technique, determines the
spatial distribution and relative abundance of versatile endogenous
metabolites in tissues. Meanwhile, matrix selection is generally regarded
as a pivotal step in MALDI tissue imaging. This study presents the
first report of a novel MALDI matrix, 2-hydroxy-5-nitro-3-(trifluoromethyl)pyridine
(HNTP), for the in situ detection and imaging of
endogenous metabolites in rat liver and brain tissues by MALDI-MS
in positive-ion mode. The HNTP matrix exhibits excellent characteristics,
including strong ultraviolet absorption, μm-scale matrix crystals,
high chemical stability, low background ion interference, and high
metabolite ionization efficiency. Notably, the HNTP matrix also shows
superior detection capabilities, successfully showing 185 detectable
metabolites in rat liver tissue sections. This outperforms the commonly
used matrices of 2,5-dihydroxybenzoic acid and 2-mercaptobenzothiazole,
which detect 145 and 120 metabolites from the rat liver, respectively.
Furthermore, a total of 152 metabolites are effectively detected and
imaged in rat brain tissue using the HNTP matrix, and the spatial
distribution of these compounds clearly shows the heterogeneity of
the rat brain. The results demonstrate that HNTP is a new and powerful
positive-ion mode matrix to enhance the analysis of metabolites in
biological tissues by MALDI-MSI.