Mass cytometry

Mass cytometry is a mass spectrometry technique based on inductively coupled plasma mass spectrometry and time of flight mass spectrometry used for the determination of the properties of cells (cytometry). In this approach, antibodies are conjugated with isotopically pure elements, and these antibodies are used to label cellular proteins. Cells are nebulized and sent through an argon plasma, which ionizes the metal-conjugated antibodies. The metal signals are then analyzed by a time-of-flight mass spectrometer. The approach overcomes limitations of spectral overlap in flow cytometry by utilizing discrete isotopes as a reporter system instead of traditional fluorophores which have broad emission spectra. Tagging technology and instrument development occurred at the University of Toronto and DVS Sciences, Inc. CyTOF (cytometry by time of flight) was initially commercialized by DVS Sciences in 2009. In 2014, Fluidigm acquired DVS Sciences to become a reference company in single cell technology. In 2022 Fluidigm received a capitol infusion and changed its name to Standard BioTools. The CyTOF, CyTOF2, Helios (CyTOF3) and CyTOF XT(4th generation) have been commercialized up to now. Fluidigm sells a variety of commonly used metal-antibody conjugates, and an antibody conjugation kit. Imaging mass cytometry (IMC) is a relatively new imaging technique, emerged from previously available CyTOF technology (cytometry by time of flight), that combines mass spectrometry with UV laser ablation to generate pseudo images of tissue samples. This approach adds spatial resolution to the data, which enables simultaneous analysis of multiple cell markers at subcellular resolution and their spatial distribution in tissue sections. The IMC approach, in the same way as CyTOF, relies on detection of metal-tagged antibodies using time-of-flight mass spectrometry, allowing for quantification of up to 40 markers simultaneously. CyTOF mass cytometry data is recorded in tables that list, for each cell, the signal detected per channel, which is proportional to the number of antibodies tagged with the corresponding channel's isotope bound to that cell.