By using a variety of transition metals to tag cellular proteins, researchers have simultaneously measured up to 34 characteristics in individual cells. That's more than double the number tracked with previous methods.
Flow cytometry has long been an important tool for discovering and characterizing subtypes of cell. It uses fluorescent markers to concurrently follow the activities of up to 15 cellular parameters. In 'mass cytometry', however, Garry Nolan of Stanford University in California and his colleagues used mass spectrometry to measure changes in the levels of metal-tagged proteins. Mass spectrometry has high resolution, allowing many signals to be measured at once.
The authors monitored fluctuations in 34 parameters in healthy human bone-marrow cells, and uncovered several new cell-signalling events. They also followed the cells' responses to the cancer drug dasatinib.