The disclosed subject matter provides a nanoaperture having a bottom surface and a side wall comprising gold. A surface of the side wall is passivated with a first functional molecule comprising polyethylene glycol. The bottom surface of the nanoaperture can be functionalized with at least one second molecule comprising polyethylene glycol, for example, a silane-PEG molecule. The second molecule can further include a moiety, such as biotin, which is capable of binding a target biomolecule, which in turn can bind to a biomolecule of interest for single molecule fluorescence imaging analysis. Fabrication techniques of the nanoaperture are also provided.