Graphene Biophysics, Biosensing & Superresolution

• Applicants: Dr. Izabela Kaminska, Ph.D.; Professor Dr. Philip Tinnefeld
• Subject Area: Biophysics ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 459594986

The overarching goal of this project is establishing graphene as a novel substrate platform for graphene biosensing, biophysics and superresolution microscopy. The key to this are DNA origami nanostructures which overcome the chemical inertness of the graphene and create biocompatibility by acting as a chemical adapter. In addition, the modularity and addressability of the DNA origami structures enable the placement of molecular units with nanometer precision relative to each other and to the graphene surface. We recently developed a strategy for immobilizing functional DNA origami structures on graphene using pyrene-modified adapter strands as a universal adhesive overcoming previous problems of denaturing DNA origami structures immobilized on graphene. On the basis of the DNA origami structures, immobilized on graphene, we are striving for novel biophysical and biosensory assays based on the fact that graphene serves as a distance-dependent quencher for the fluorescence of individual molecules. In comparison to fluorescence resonance energy transfer, the distance dependency is flatter and reaches a value of 50% fluorescence quenching at approx. 18 nm. The quenching of the fluorescence is used to detect DNA and proteins as well as to study the conformational dynamics of individual biomolecules. In addition, the distance-dependent fluorescence is used as a parameter to determine the z-positions of individual molecules and, in combination with 2D location-based super-resolution microscopy, to achieve an isotropic resolution below 10 nm. This resolution should initially be used for the visualization of DNA nanostructures and dynamic processes.

• DFG Programme: Research Grants