Self-assembly of Pt(IV) 6 into NPs quantitatively maximized cellular uptake of Pt, which was easily interfered with by macropinocytosis inhibitors. (a–d) Pt uptake into (a, b) A2780 and (c, d) A2780cis cells after 4 and 18 h of exposure to cisplatin, P6 NPs, or P6 Soln at Pt concentrations of (a, c) 50 and (b, d) 100 μM. (e, f) Prior exposure of A2780 and A2780cis cells to (e) EIPA and (f) cytochalasin D reduced uptake of Dil-P6 NPs in a dose-dependent fashion.