Folding of Molecular Wires published in Nature Nanotechnology
A team of researchers from Aarhus University and Harvard University has developed a method to wire single molecule polymers in predesigned paths on board made of DNA.
Conjugated polymers have several useful applications, owing to their ability to conduct current and emit light. This is e.g. used in organic light emitting diodes (OLEDs) in commercial displays, and TV monitors. One of the visions of the field of molecular electronics, where single molecules constitute the components in electronic circuits, is to use individual conjugated polymers as electronic or optical wires. So far, this remains to be a vision due to the lack of methods to handle individual molecules, and control their relative position and connection.
In the article, published in Nature Nanotechnology on August 31, 2015, the researchers describe the development of a new method to synthesize conjugated polymers containing short DNA strands, extending from each repeat unit along the polymer. To place the polymer, a rectangular DNA origami “board” of dimensions 100×70 nm2 has been formed by self-assembly of hundreds of DNA strands. By coding a specific route on the surface of the DNA board with DNA strands that match the DNA on the polymer, the polymer assembles along the specific path. It allows folding of the polymer in linear and curved paths, as shown for the U-shaped routing of the polymer in Figure 1.
In collaboration with the Harvard team it became possible to route the polymer in 3 dimensions, and image the polymer by the super high resolution microscopy technique called PAINT.
Figure 1 Illustration and AFM image of poly(DNA-phenylene vinylene) on DNA origami.
“We are still very far from realizing the dream of molecular electronics, but this is a very important step since it is the first method to actually control the positioning and shaping of individual polymer wires”, says professor Kurt Gothelf who led the team, and he continues “It furthermore provides a unique opportunity to isolate and characterize single molecule polymers, and to study the relation between shape an properties”.
The project was performed in collaboration between research groups lead by Mingdong Dong, Victoria Birkedal, Flemming Besenbacher and Kurt Gothelf at the Danish National Research Foundation: Center for DNA Nanotechnology (CDNA) at iNANO, Alexander Zelikin at Department of Chemistry at Aarhus University, research groups at the Wyss Institute at Harvard University lead by William Shih, Peng Yin, and Ralf Jungman who is currently at the Max Planck Institute for Biochemistry in Munich.