Fig. 3. Scanning electron microscopy characterization of the nanostructured protein films. (A) SEM micrographs showing a comparison of the surface of the PDMS stamp and the surface of the protein patterned film, in which the nanostructure patterns are perfectly replicated. (B) From left to right, the optical image and SEM image of the film cross-section; the patterned protein films are self-standing. On the right a higher magnification SEM image of the protein film is shown.