Fabrication and arrangement of "clickable" nanowires by the single-particle nanofabrication technique

Focusing of photons or charged particles into a small spatial area has been believed to be indispensable for "top-down" miniaturization in conventional micro- or nanolithographic techniques. Here, we describe a fabrication technique with the concept of "a nanowire produced by a particle", released from these limitations, using "Clickable" nanowires to construct highly controlled biological macromolecular materials. The present paper demonstrates the formation of nanowires composed of synthetic polymers by the single-particle nanofabrication technique (SPNT). The fabrication of nanowires composed of a polystyrene derivative with an alkyne "click" function, poly(styrene-co-4-ethynylstyrene) (PSES), was confirmed by atomic force microscopy. Alkyne moieties in PSES achieve an extremely high value of cross-linking efficiency compared with unsubstituted polystyrene. Alkyne groups on the surface of PSES nanowires were modified by polymer materials and proteins via copper-catalyzed alkyne/azide cycloaddition reactions and avidin-biotin interactions, respectively. PSES and its nanowires were thus revealed to be suitable materials for the fabrication of nanostructures and the introduction of various functional materials, including biomacromolecules, by surface modification. With "Clickable" nanowires fabricated by SPNT, it should be possible to trigger the development of the architecture of biomacromolecular nanomaterials.