Fig. 6. Cell spreading in relation to substratum geometry. B16 cells were cultured on fibronectin substrata prepared with µCP and labelled for fibronectin (red) and actin (green). (A) On a homogeneous substratum (hs), actin filaments are distributed throughout the cell periphery. (B,C) If the space between dots is 2 µm (B: 0.1 µm² squares 1 µm apart, C: 1 µm² squares 2 µm apart) cells spread as on a homogeneous substratum. (D-I) Cell growth on patterned substrata of 9 µm² dots with spacing as indicated in the right-hand corner. (D-F) With distances of 5-20 µm between dots, cells spread and the actin cytoskeleton formed stress fibres between adjacent dots. (G-I) At a distance of 25 µm, spreading was limited and cells became triangular, ellipsoid or round. Scale bar: 10 µm.