Fig. 4: B₁₂Br₁₂²⁻-assisted phalloidin-TRITC transport into living HeLa cells.

Cells were incubated with 0.5, 2.5 and 5 µM phalloidin-TRITC (red, from left to right) in the absence (top row) and presence of different concentrations of B₁₂Br₁₂²⁻ cluster (10, 25 and 50 µM; second, third and fourth rows, respectively) in HKR buffer for 3 h, subsequently stained with Hoechst (blue), washed for 5 min with 0.1 mg ml⁻¹ heparin in HKR buffer and imaged by confocal fluorescence microscopy; bright-field images in insets. Representative images of two biological replicates. Staining results were insensitive to sequence of addition (Supplementary Note 2). Scale bars, 50 μm.