SpeakerProf. Tim Liedl, Physics, LMU Host: Omar Saleh
Date and LocationWednesday February 24, 2016 11:00am to 12:00pm
We use the DNA origami method  for the fabrication of functional self-assembled nanoscopic objects and materials . By offering attachment sites for active nano-components on these DNA objects, we have realized complex and nanometer-precise assemblies of fluorophores and plasmonic nanoparticles .
Currently we are exploring plasmonic nanoantennas made by DNA origami that can be used as reliable and efficient probes for surface enhanced Raman spectroscopy (SERS). The nanoantennae are built up by pairs of gold nanoparticles on DNA origami templates at separation distances between 9 nm and 4 nm in order to achieve plasmonic coupling and the formation of strong plasmonic ‘hot spots’ .
In recent, unpublished experiments we studied force interactions between biomolecules. Well-established techniques such as atomic force microscopy and magnetic or optical tweezers are usually applied to investigate protein folding or biopolymer – particularly DNA – elasticity. Here we present a nanoscopic DNA origami based single-molecule force spectroscopy device without any physical connection to a micrometer-sized bead or cantilever. We exploit the entropic elasticity of single-stranded DNA to apply tension on a system mounted on the device  and single-molecule Förster Resonance Energy Transfer (smFRET) is used as a readout to study two dynamic systems under different tensions: the transition behavior of a Holliday junction and the bending of a DNA promotor sequence induced by the TATA-binding protein (TBP). We are able to generate reliable single-molecule force spectroscopy data in the piconewton range in a high throughput fashion. Our DNA origami force spectrometer can in principle be employed with a wide variety of DNA interacting biomolecules.
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