Confocal microscopic images of B16F1 (green) invasion of HUVEC network (red).

<p>Magnetically labeled B16F1 cells were arrayed at 10 cells/spheroid with 250 µm interval over the HUVEC network, and images surrounding the HUVEC network were taken before (A–C) and after the 24 h co-culture (D–G). The representative sectional view of the HUVEC network before co-culture with B16F1 (B, C) and invasive points of B16F1 after a 24 h culture (E–G). Scale bar: 10 µm.