CyTOF^® Mass Cytometry

Cells stained with metal-conjugated antibodies and metallointercalators are introduced individually into an Inductively Coupled Plasma, were the cells are atomized and ionized. The atomic ions are extracted into the ion optics and time-of-flight regions where they are separated by mass and counted. The elemental signature of the cell includes the element tags introduced with the antibodies and metallointercalators. The presence of the metal tag indicates that the antibody found and bound the target biomarker, and the intensity of the signal is directly proportional to the number of antibodies bound per cell (ABC). The elemental composition of each cell is separately analyzed. In a typical cell analysis experiment, four minutes of raw data collection is sufficient for analysis of 100,000 cells independent of the number of metal tags (one or all 33).

It is important to note that cells without any tagging metals cannot be detected by mass cytometry: only element tags can be registered with high sensitivity and specificity, and therefore there is no "auto-fluorescence"-like effects. Metal tags are chosen from rare elements whose natural concentration in a biological sample is below the detection limit. Unstained cells are "transparent" to the mass cytometer. A complete description of the instrument can be found in Bandura et al, 2009.