Simultaneous Imaging of Small Metabolites and Lipids in Rat Brain Tissues at Atmospheric Pressure by Laser Ablation Electrospray Ionization Mass Spectrometry

摘要

Atmospheric pressure imaging mass spectrometry is anrapidly expanding field that offers advantages in the abilitynto study biological systems in their native condition,nsimplified sample preparation, and high-throughput experiments.nIn laser ablation electrospray ionization (LAESI),nthe native water molecules in biological tissuesnfacilitate sampling by a focused mid-infrared laser beam.nThe ionization of the ablated material is accomplished bynelectrospray postionization. In this work, we demonstratenthat the imaging variant of LAESI simultaneously providesnlateral distributions for small metabolites and lipidsndirectly in rat brain sections. To cope with the fragilennature and potential dehydration of the brain tissue duento drying in the ambient environment as well as tonminimize analyte redistribution, a Peltier cooling stage isnintegrated into the LAESI imaging system. We demonstratenthe utility of high-resolution (m/Δm > 6000) timeof-nflight mass spectrometry with LAESI to deconvolutenspatial distributions of different chemical species withnidentical nominal mass. To help with the evaluation of thenmassive data sets, Pearson colocalization maps are calculatednfor selected small metabolites and lipids. We shownthat this approach reveals biologically meaningful correlationsnbetween these two classes of biomolecules.