Production of nanostructures of DNA on surfaces

Nanopatterns of thiolated single-stranded DNA (ssDNA) are produced by using an atomic force microscopy (AFM)-based lithography technique known as nanografting. Under high shear force, AFM tips displace resist molecules within a self-assembled monolayer, while ssDNA molecules adsorb chemically onto the exposed gold area through the sulfur headgroup. Nanostructures of ssDNA are characterized directly and in situ by using the same tip. Lines as narrow as 10 nm have been produced. The ssDNA molecules stand up on the gold surfaces and adapt a stretched conformation. In situ and real-time imaging studies have revealed that DNA molecules within the nanostructures are accessible by enzyme molecules.