Byun, S. et al. Proc. Natl. Acad. Sci. USA 110, 7580–7585 (2013).

Cells that move through the body must squeeze through tight spaces, and the metastatic potential of cancer cells may depend on their deformability. Several methods are used to monitor cellular mechanical properties; Byun et al. now describe a sensitive and high-throughput option. By introducing a constriction in the microchannel of a suspended microchannel resonator, the researchers monitor a cell's buoyant mass, its entry velocity into the constriction and its transit velocity through the constriction, at a rate of 105 cells per hour. For many cell types, overall passage time depends on cell mass, but this is not the only important parameter. Cell deformability predominantly affects entry velocity, cell friction mainly affects transit velocity, and both of these properties can contribute to the shorter passage time of cells with higher metastatic potential.