Katharina Brassat1 2 Saminathan Ramakrishnan1 Julius Bürger1 Alexander Stratmann1 Guido Grundmeier1 Adrian Keller1 Jörg K. N. Lindner1 2

1, Univ of Paderborn, Paderborn, , Germany
2, Center for Optoelectronics and Photonics, Paderborn, , Germany

The ability to design nanoscale bio-hybrid material surfaces with tailored morphology is crucial for the development of future devices for life science and molecular electronics. The creation of hierarchical nanostructures allows for a versatile approach to combine different materials classes into advanced functional nanopatterns. In this paper, we demonstrate the site-selective adsorption of DNA origami into hexagonally arranged nanoscale metallic surface pre-patterns.

DNA origami are widely used 2D-nanoobjects with tailored shape, which are fabricated by self-folding of designed DNA strands. DNA origami with triangular shape, as used in this work, tend to arrange themselves into close-packed layers if adsorbed onto solid surfaces, where they can be used as templates for molecular lithography, e.g. for the creation of protein or nanoparticle arrays. For the creation of protein or nanoparticle arrays with tailored periodicity, we investigate the DNA origami adsorption on pre-patterned surfaces.

To this end, we used nanosphere lithography to create self-arranged antidot pre-patterns with tailored feature sizes in the range of 100 - 400 nm on large substrate areas. The antidot patterns exhibit hexagonally arranged circular free substrate areas in metal thin films, creating simultaneously a periodical topography as well as a chemical contrast on the surface.
We demonstrate the positioning of single DNA triangles site-selectively inside these antidot-patterns in a gold thin film on a SiO2 surface. The influence of the adsorption conditions, i.e. buffer, salt and origami concentration and incubation time, on the yield of adsorbed DNA triangles is investigated. The functionalization of the origami prior to the deposition process is shown to allow for precise positioning of nanoparticles along with the origami. The created hierarchical nanopatterns of DNA with attached nanoparticles inside the antidots are investigated by AFM and SEM.

As the pre-patterning technique as well as the DNA origami positioning are easily applicable on large surface areas and the number of adsorbed origamis per antidot can be set by the pre-pattern dimensions, this approach largely enhances the flexibility of molecular lithography.