Titration and validation of osmium tetroxide staining for mass cytometry

To evaluate osmium tetroxide as a staining reagent for mass cytometry analysis Conclusion: Staining single cell suspensions with a 300nM solution of OsO4 resulted in a strong cellular osmium signal that was optimally detected in the Os-192 channel, consistent with the expected natural osmium isotopic abundance ratios. The addition of OsO4 labeling to antibody-stained samples did not noticeably alter antibody staining intensity. Samples were loaded with EQ beads (Fluidigm) and data were acquired at an event rate of <500evt/s. The stability of signal intensity over time was confirmed to be within tolerable ranges, and the data were normalized using a bead-based normalization algorithm (Fluidigm).