Confocal microscopy of HER2-positive (upper panel) and HER2-negative (lower panel) cells exposed to ZHER2-DyLight-488.

<p>SK-BR-3 and MDA-MB-468 cells were plated at 2×10⁴ cells/chamber and exposed to Z_HER2-DyLight-488 at 0.5 µg/ml. After a 30 min loading step, cells were rinsed and incubation was continued for indicated period of time at 37°C. A half hour before imaging, the nuclei were counterstained with Hoechst 33342 at 0.2 µg/ml. Images were acquired using Zeiss LSM 510 microscope.