Carbon nanotubes as probes for atomic force microscopy

Tip-derived artifacts remain one of the chief limitations of atomic force m icroscopy (AFM) when attempting to measure sub-nanometre structures. Carbon nanotubes represent ideal structures for use as AFM tips because of their small diameter, high aspect ratio and high strength. We attached single car bon nanotube AFM tips using a novel are discharge method. Using these modif ied tips, we successfully imaged a protein filament found in sponge spicule s of Tethya aurantia. We report a modular stave-like structure for the prot ein filament that was previously unobservable with conventional AFM cantile vers.