Bodenmiller, B., et al. Nat. Biotechnol. advance online publication (19 August 2012).

In mass cytometry, metal ions conjugated to binding reagents are used for molecular labeling and are read out by inductively coupled plasma mass spectrometry. The technique has dramatically increased the number of cellular parameters that can be detected in a sample (34 simultaneous measurements, compared to 12 for fluorescence). Bodenmiller et al. now demonstrate mass-tag cellular barcoding (MCB) to increase the throughput of this technique via multiplexing. They use binary combinations of seven lanthanide metal ions to multiplex samples from an entire 96-well plate. They apply MCB to detect multiple cell-surface and intracellular components of signaling pathways in human peripheral blood mononuclear cells over time, in multiple donors and in the presence or absence of a panel of inhibitors at several doses.