MALDI MS Imaging at Acquisition Rates Exceeding 100 Pixels per Second

• Published in: Journal of the American Society for Mass Spectrometry 2019-02, Vol.30 (2), p.289-298
• Main Authors: Bednařík, Antonín, Machálková, Markéta, Moskovets, Eugene, Coufalíková, Kateřina, Krásenský, Pavel, Houška, Pavel, Kroupa, Jiří, Navrátilová, Jarmila, Šmarda, Jan, Preisler, Jan
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; ANIMAL TISSUES; Anticancer properties; Bioinformatics; Biotechnology; CARCINOMAS; Chemistry; Chemistry and Materials Science; Colorectal cancer; DISTRIBUTION; Electrodes; Equipment Design; GALVANOMETERS; HT29 Cells; Humans; Image acquisition; IMAGE PROCESSING; Image Processing, Computer-Assisted - methods; Image resolution; IMAGE SCANNERS; INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ION SOURCES; IONIZATION; Ions; Laser beams; LASER RADIATION; Lasers; Low speed; MASS SPECTROMETERS; Mass spectrometry; MASS SPECTROSCOPY; OPTICAL EQUIPMENT; OPTICAL SYSTEMS; Organic Chemistry; Pixels; Proteomics; RADIOLOGY AND NUCLEAR MEDICINE; Research Article; RESOLUTION; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - instrumentation; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Spheroids, Cellular - chemistry; TIME-OF-FLIGHT METHOD; Tissues
• ISSN: 1044-0305; 1879-1123
• DOI: 10.1007/s13361-018-2078-8

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