Anisotropic silk film inspired by reed leaves for biomedical application

The anisotropic topography of film surfaces plays an important role in regulating cell attachment, morphology, and differentiation. Herein, anisotropic silk film with two different ridge/groove microstructures was created by using reed leaves as templates. The ridge width of silk films derived from the positive and negative of reed leaf were about 279.8 μm and 242.2 μm, respectively. The silk film features a stable β-sheet structure after ethanol treatment. The U87 cells grown on the anisotropic and flat silk film show orientation angles of 13.6° and 46.1°, indicating a directional growth of cells along with the ridge.