In order to better investigate the role of deep grooves created on the stretch of silk fibers, imaging of the cross-sectional area of the films as well as the patterned surface of the 30/70 monolayer sample, the bilayer 70/30-alginate sample without the drug, and the bilayer 70/30-alginate sample with the ascorbic acid drug, were performed by scanning electron microscopy. As shown in Figure 4-18, the silk fibrils in all three samples were stretched along the grooves, and a good bond was established between this layer containing the patterned silk and alginate substrate, with or without the drug. Figure 18-4 (b) shows the 30/70 film made below with a layer of alginate on it.