The combined influence of surface topography and charge of a polymer surface on the adsorption of the protein avidin has been investigated. Atomic force microscopy contact mode imaging and charge writing were used to create defined topographical roughness and electrostatic charge patterns on the surface of polystyrene. Increased avidin adsorption was found on nanometer-size topographical patterns, but the adsorption remained unaffected by electrostatic patterns.

Surface charge patterns generated by atomic force microscopy-based charge writing were used to pattern amyloid-like peptide fibrils on a solid substrate. Fibrils of the short peptide TTR105-115 were encapsulated inside water droplets of a water-in-perfluorocarbon oil emulsion and retained their rod morphology. They were observed to deposit selectively with a lateral resolution of approximately 1 microm onto negatively charged patterns on a polymethyl-methacrylate substrate.