Dolphins from University of Aarhus logo folded in DNA
In an article in the journal ACS Nano, a group of researchers from the Centre for DNA Nanotechnology (CDNA) and the Interdisciplinary Nanoscience Centre (iNANO) at the University of Aarhus describe how they can fold DNA in arbitrary nanostructures using newly developed software.
For example, the researchers formed the dolphins from the University of Aarhus logo in DNA measuring just 200 nanometres, the equivalent of a hundredth of the width of a human hair. Making the dolphins from the university's logo involved designing 216 pieces of DNA that were ordered from a local DNA synthesis company. These were mixed in the laboratory with a longer DNA strand extracted from a virus, which assemble themselves in the desired two-dimensional dolphin-like shape by means of heating and cooling. This folding technique is called DNA origami – named after the Japanese art of folding paper. It was recently pioneered by Paul W. Rothemund from the California Institute of Technology, USA. To confirm that the scientists had actually succeeded in forming the DNA pieces in the shape of the university's dolphins, a subsequent scanning was done using atomic force microscopy (AFM). It was also demonstrated that the DNA dolphins could be designed with flexible tails, and could be assembled in pairs in a constellation resembling the two dolphins in the University of Aarhus logo.
The studies were carried out in interdisciplinary collaboration between three research groups at the Departments of Molecular Biology, Physics and Astronomy, and Chemistry, all of which are affiliated with the Centre for DNA Nanotechnology (CDNA). The DNA structures referred to were designed and assembled by Professor Jørgen Kjems' group at the Department of Molecular Biology. He says:
“The DNA origami method is an entirely unique way of using self-assembling DNA in complex structures right down to the scale where the molecules in our bodies communicate with each other. The software we designed makes it much quicker and more reliable to design arbitrary DNA origami structures. Where it used to take weeks to put structures together manually, we can now do it in a few seconds.”
The interdisciplinary Centre for DNA Nanotechnology was set up in 2007 as one of the Danish National Research Foundation's Centres of Excellence. One of the main themes for the centre's research is the application of DNA as a material that can be programmed to assemble the nanoscale building blocks (NBBs) for functional nanostructures. Professor Kurt Gothelf, Director of CDNA, says:
“It's really incredibly fascinating that more than 200 pieces of DNA can be programmed to form complex predesigned structures on a nanoscale.” He goes on:
”We've launched several research projects where we use the method to assemble functional nanostructures for use in fields such as combatting disease, diagnostics and electronics.”
CDNA is part of the Interdisciplinary Nanoscience Centre (iNANO), headed by Professor Flemming Besenbacher, whose group was responsible for visualising the DNA dolphins and their flexibility using atomic force microscopy (AFM). Professor Besenbacher says:
“This is an example of very successful interdisciplinary collaboration between Jørgen Kjems' group, Kurt Gothelf's and my own. It's this type of interdisciplinary collaboration that will be strengthened even further when the new iNANO House at the University of Aarhus is finished and the three research groups move into the same building.”
The researchers' work was recently published in the online edition of ACS Nano and is being printed on 24 June 2008. Read the abstract here: http://pubs.acs.org/cgi-bin/abstract.cgi/ancac3/asap/abs/nn800215j.html. You need to subscribe in order to download the article. You can also obtain the article by contacting the address below. The software is publicly accessible at: http://www.cdna.dk/origami.
Centre for DNA Nanotechnology (CDNA): www.cdna.dk
Contact person
Professor Jørgen Kjems
Department of Molecular Biology
University of Aarhus
Tel: +45 8942 2686
E-mail: jk@mb.au.dk
Website: http://www.rna.dk/jk/
Figure 1: Researchers designed the DNA dolphin with a flexible tail, which could be observed using an atomic force microscope (three images at left). Two dolphins were also designed so that they were assembled in pairs in the test tube (image at right).
Figure 2: The researchers began by cutting a dolphin out of the University of Aarhus logo, after which it was used as a template for designing a dolphin-like DNA structure. After producing this in the laboratory, AFM images were taken of the DNA structure thus formed. In the University of Aarhus logo to the right, an image of the DNA dolphin is reinserted.