Varying surface hydrophobicities of coatings made of recombinant spider silk proteins

The engineered spider silk protein eADF4(C16) reveals similarities to amphiphilic block copolymers. Drop cast of protein solutions on different hydrophobic as well as hydrophilic templates out of different starting solvents (hexafluoroisopropanol, formic acid and aqueous buffers) generated silk films varying in structure and surface properties. Here, the underlying secondary structure of the proteins, the mechanical integrity at increased temperatures, homogeneity and surface topography of silk films, as well as the wettability were investigated in detail. Interestingly, the used templates had impact on microphase separation of the silk molecules as seen by the content of beta-sheet structures; as well as on silk film surface hydrophobicities.