Fig. 3. Cellular peptide uptake assisted by different boron clusters.

HeLa cells were incubated with 1 µM TAMRA-R₈ in the absence (‘no cluster’) or presence of 10 µM boron cluster diluted in HKR buffer for 1 h, washed with DMEM without phenol red and imaged by confocal fluorescence microscopy. The micrograph in the bottom right panel refers to incubation with the enantiomeric (hydrolysis-resistant) TAMRA-D-R₈ (1 μM) and B₁₂Br₁₂²⁻ (1 μM) for 30 min. Brightness and contrast of TAMRA-D-R₈ were adjusted to avoid saturation; see Extended Data Fig. 6d for comparison with controls. Representative images of two biological replicates. Staining results were insensitive to incubation time (Supplementary Note 1). Scale bars, 50 μm.