Figure 4.

XRF elemental maps of Os and Br acquired from cryo‐fixed and freeze‐dried A549 (human lung) cancer cells treated with a) 1, b) 3 or c) 5×IC₅₀ of S,S ‐2 (30, 90 or 150 μM) for 24 h, showing Os‐Br co‐localisation in small vesicle‐like areas. Maps were collected using 100 nm step size and 0.1 s dwell time. The calibration bar is in pg mm⁻². Data were processed using the PyMCa toolkit developed by the ESRF, ^[15] and images generated in ImageJ. ^[16]