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DNA-based functional lattices

Periodic Reporting for period 1 - DNA Funs (DNA-based functional lattices)

Reporting period: 2019-04-01 to 2020-09-30

Advances in design and low-cost production of DNA nanostructures allow us to challenge nature in nanoscale positioning. By combining the assembly power of
DNA origami with top-down lithography we intend to fabricate functional nanostructured materials designed on the molecular level while reaching macroscopic dimensions.
Three objectives have been defined:
1. We design and implement DNA structures that are organized on patterned surfaces and assemble into interpenetrating 3D networks that exhibit the highest possible contact area for electron donor and acceptor molecules in organic photovoltaic devices. So far we adopted lithography methods to pattern DNA origami on substrates and placed DNA origami tubes on silica substrates. In the long run we intend to study and potentially boost energy conversion rates in organic solar cells.
2. Custom-tailored photonic crystals built from lattices of DNA origami structures will control the flow of light. We designed and characterized a variety of 3D DNA origami crystals and can now reliably silicify these structures.
3. We intend to observe “Dirac plasmons” in DNA-assembled particle lattices. Such topologically protected states are sought after for the coherent and loss-less propagation of information. Together with objectives 2 we here intend to develop new building blocks for next-generation all-optical circuits.
In objective 1 we designed DNA origami tubes for dye positioning and managed to adopt a patterning protocol that allows us to place DNA origami structures on silica substrates. The postdocs and students working on the project also explored the successful binding of electron acceptors to DNA origami structures. The structures have been characterized with gel electrophoresis, TEM and absorption and fluorescence spectroscopy.
In objective 2 we implemented a variety of 2D and 3D DNA origami crystals. Together with the PhD students who worked on the projected the team established robust protocols to silicify the DNA origami crystals. Transmission and scanning electron microscopy (SEM and TEM) and small angle X-ray scattering (SAXS) proved to be suitable methods for studying these lattices. Theoretic modelling of photonic bandgaps has been employed which led to the design and experimental implementation of a specific DNA origami crystal.
In objective 3 we achieved zigzag chains of metal nanoparticles on DNA origami templates. The objects were characterized with TEM and darkfield spectroscopy. Darkfield microscopy revealed polarization-dependent switching of intensity peaks. We are currently eliminating the effects of polarization induced optical distortions. We further designed and implemented 2D lattices that can lay the foundation for topological insulation.
In the process of establishing the absorption and scattering spectroscopy with the DNA origami crystals we discovered a new way to monitor DNA origami folding.
Placing 3D DNA origami objects on patterned surfaces is a major achievement.