Fig. 4

Patterned silk membrane guides the cell arrangement. Silk fibroin solution (a) was used to fabricate flat (b and c) and patterned (d and e) silk membranes. b, d Macroscopic pictures show that the silk membranes were clear enough to allow visualization of the letters below. c, e SEM pictures revealed the surface morphology of the membranes. f The cell alignment on silk membranes were compared by F-actin staining. The right panels show the merged picture of the left panels (F-actin staining) and the middle panels (DAPI staining). White arrows indicate the direction of the grooves on patterned silk membranes. g PDLSCs were seeded and differentiated by induction medium on silk membranes with or without substance P (SP). Pictures were taken at day (d) 1, 4, 7, and 14 after induction. White arrows indicate the direction of the grooves on patterned silk membranes. Cellular orientation angles (h) and cellular aspect ratios (i) of seeded cells were determined. All other groups were compared to patterned silk membranes at each time point in the statistical analysis. Results are shown as mean ± SEM. **p < 0.001. N.S. not significant