2D materials with a thickness of a single atom are of broad interested for alternative energy sources, batteries and medical applications. The elaboration on the outstanding properties of graphene has been rewarded with the noble price in 2014 and underlines the impact of this material in the field ever since.
In microscopy applications, graphene can be used as an energy acceptor absorbing the energy of a fluorescent molecule close to its surface. Therefore, the brightness of such a fluorescent molecule depends strongly on its distance to graphene: The closer they are the more energy is transferred and this reduces the fluorescence. By measuring the brightness scientists can determine distances between fluorophore and graphene surface of only about 40 nanometers. This allows to measure scales as small as a molecule itself.
The team of Prof. Philip Tinnefeld (LMU Munich) and their colleagues from the Polish Academy of Science Warsaw have now optimized the necessary graphene transfer to glass and investigated the influence of graphene on different fluorescent molecules. To accurately place these molecules with a defined distance on graphene, the scientist took advantage of tiny biological structures. They are composed of nucleotides - the same building blocks of the human DNA. The scientists are able to program the sequence of the nucleotides to form arbitrary structures. They are named “DNA origami structures” referring to the Japanese tradition of folding paper into different forms and shapes. The groups from Munich and Warsaw used the method to form nanometer pinboards and equipped them with a whole series of self-designed static and dynamic structures with fluorescent molecules. They attached the structures to graphene to apply its energy transfer for the fields of biophysics, biosensing and superresolution microscopy.