Palladium-based viability staining reproduces cisplatin-based dead cell identification. (A) Live and heat-killed (55 °C for 1 h) PBMCs were mixed and incubated for 5 min at RT with 500 nM cis-dichloro-diamine-platinum(II) (cisplatin) and 500 nM dichloro-(ethylenediamine)-palladium(II) (DCED-palladium). (B) Platinum (198Pt) signal (left) in cells as in (A) was used to discriminate live (cisplatinlow) and dead cells (cisplatinhigh), which were then analyzed for their palladium signal in one palladium channel (110 Pd, middle) or across all measured palladium isotopes (right). 110 Pd is shown as an example but other Pd-channels (with the exception of 102 Pd) could be used analogously. Representative example from a total of n = 8. (C) DCED-palladium (110 Pd) and cisplatin (198Pt) in cells as in (A). (D) The frequency of dead cells within multiple different types of samples was assessed using cisplatin and DCED-palladium simultaneously (n = 48, pooled from 10 independent experiments). (E) DCED-palladium on its own can be used to discriminate live from dead cells (here heat-killed as in A). Representative example from a total of n = 48.