The practicality of matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) applied to molecular imaging of biological tissues is limited by the analysis speed. Typically, a relatively low speed of stop-and-go micromotion of XY stages is considered as a factor substantially reducing the rate with which fresh sample material can be supplied to the laser spot. The sample scan rate in our laboratory-built high-throughput imaging TOF mass spectrometer was significantly improved through the use of a galvanometer-based optical scanner performing fast laser spot repositioning on a target plate. The optical system incorporated into the ion source of our MALDI TOF mass spectrometer allowed focusing the laser beam via a modified grid into a 10-μm round spot. This permitted the acquisition of high-resolution MS images with a well-defined pixel size at acquisition rates exceeding 100 pixel/s. The influence of selected parameters on the total MS imaging time is discussed. The new scanning technique was employed to display the distribution of an antitumor agent in 3D colorectal adenocarcinoma cell aggregates; a single MS image comprising 100 × 100 pixels with 10-μm lateral resolution was recorded in approximately 70 s. Graphical Abstract.

• Klíčová slova
• 3D cell aggregates, Colorectal adenocarcinoma, Grid ion source, High throughput, Laser beam scanning, MALDI, MSI, Mass spectrometry imaging, Spheroids, TOF,
• MeSH
• buněčné sféroidy chemie   MeSH
• buňky HT-29 MeSH
• design vybavení MeSH
• elektrody MeSH
• lasery MeSH
• lidé MeSH
• počítačové zpracování obrazu metody   MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice přístrojové vybavení   metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Matrix-assisted laser desorption/ionization mass spectrometric imaging (MALDI MSI) is a well-established analytical technique for determining spatial localization of lipids in biological samples. The use of Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometers for the molecular imaging of endogenous compounds is gaining popularity, since the high mass accuracy and high mass resolving power enables accurate determination of exact masses and, consequently, a more confident identification of these molecules. The high mass resolution FT-ICR imaging datasets are typically large in size. In order to analyze them in an appropriate timeframe, the following approach has been employed: the FT-ICR imaging datasets were spatially segmented by clustering all spectra by their similarity. The resulted spatial segmentation maps were compared with the histologic annotation. This approach facilitates interpretation of the full datasets by providing spatial regions of interest. The application of this approach, which has originally been developed for MALDI-TOF MSI datasets, to the lipidomic analysis of head and neck tumor tissue revealed new insights into the metabolic organization of the carcinoma tissue.

• MeSH
• Fourierova analýza MeSH
• lidé MeSH
• lipidy analýza   chemie   MeSH
• molekulární zobrazování metody   MeSH
• nádory hlavy a krku chemie   MeSH
• počítačové zpracování obrazu MeSH
• spektrometrie hmotnostní - ionizace laserem za účasti matrice metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• lipidy MeSH