Figure 2.

Arrays of biosynthesized silica micropatterns on the hydrogel substrates. (a) Visual image shows freshly printed peptide logo with 1.2 cm width on the transparent silk hydrogel. (b) Fluorescence images of FITC-labeled R5 patterns on the silk hydrogels. (c) Visual image shows mineralized peptide logo with 1.2 cm width on the transparent silk hydrogel. (d) The whole free-standing protein system can be easily removed from the container used for gelation. (e) Schematic representation (left) and SEM images (right) show the linear array of mineralized micropatterns printed with different gap spacing between lines on the silk hydrogels. (f) AFM topography image of the silica particles on the mineralized micropatterns scanned over a 2 μm × 2 μm area. (g) The corresponding graph of the nanoparticle diameter distribution appears a sharp Gaussian distribution with a center value of ~100 nm, in a range of 50–200 nm. (h, i) SEM images show the spatial resolution of the gap spacing between two lines decreased to 20 μm and the linewidth reached ~1 μm.