DNA assemblies for structural analysis and plasmon-enhanced SERS

More than three decades ago, Nadrian Seeman proposed the co-crystallization of biological macromolecules on self-assembled DNA lattices to solve their structure by X-ray crystallography. This concept has catalyzed the success of the rapidly developing area of DNA nanotechnology. Thus far, however, arranging macromolecules in three dimensions using DNA frameworks has not been achieved, mainly because the reported DNA lattices lack sufficient rigidity and / or cavity size to host sizeable guest molecules. We therefor developed a DNA origami-based crystal that offers space for up to 30 nm large particles. We will further optimize our crystal growth conditions to achieve single-crystals. Our DNA lattices will be used for structural analysis of macromolecules placed within the cavities using small angle X-ray scattering (SAXS). In close collaboration with the Nickel group (A07) we intend to use emerging and for our samples perfectly suited methods like nano-SAXS and free electron lasers (FEL). To match the high beam intensities of these methods we will make use of our ability to silicify our DNA structures, which will increase their thermal and mechanical stability. In a second project, we will harness our generated experience to place metallic (Au and Ag) nanoparticles and nanorods with literally nanometer precision on DNA origami. In cooperation with the partners within this consortium we will deposit these complexes on lipid membranes where we can actuate the DNA origami structures with controlled light-matter interaction. Further, surface enhanced Raman spectroscopy (SERS) will be performed on macromolecules translocating through DNA-assembled nanopores. These pores will carry plasmonic antennas enabling the acquisition of single-molecule Raman signals.