Stimulated emission depletion (STED) nanolithography allows nanofabrication below the diffraction limit. Recently, it was applied to nanoanchors for protein fixation down to the single molecule level. We now combined STED nanolithography with laser-assisted protein adsorption by photobleaching (LAPAP) for optical and selective attachment of proteins to subdiffractional structures. In turn, STED was used for imaging of fluorescently tagged streptavidin to reveal protein binding to STED-lithographically patterned acrylate structures via LAPAP. Protein localization down to 56 nm spots was achieved using all-optical methods at visible wavelengths.
Keywords: biofunctionalization; laser-assisted protein adsorption by photobleaching; nanolithography; stimulated emission depletion; two-photon absorption; two-photon lithography.