Highlights 2007

About the centre

The Centre for DNA Nanotechnology (CDNA) was established on March 1, 2007. The first year the center has published 33 articles within the field and a series of highlights from the research is presented in the following.

Design and folding of DNA structures

One of the central aspects of the research at CDNA is to apply and investigate the ability of DNA to selforganize into predesigned structures. Based on a report from Caltec (Rothemund, Nature 2006), we have studied the folding of a 7200 nucleotide long viral DNA sequence with 255 short synthetic DNA sequences. We have created a 100*100 nm ”blanket” of DNA. The structures are immobilized in a surface and imaged by atomic force microscopy (AFM). By inserting short hairpin loops on top of the structure we have written the center abbreviation CDNA.

For the design of yet more complex structures a software packet for the design of DNA sequences has been developed at the center. Inspired by the dolphins in the logo of the University of Aarhus, we have designed a 2D dolphin structure with a length of approx. 200 nm and imaged the structure by AFM. As it appears from the images above, the structure can be encoded to form a dolphin dimer. Furthermore, the tail of the dolphin is flexible and can be imaged in different positions. In the next phase of this work we will be designing dynamic 3D structures.

Self-organization of DNA bases

By use of scanning tunneling microscopy (STM) it has been possible to record images on the nano-scale of monolayers of the molecule cytosine on a gold surface. Cytosine is one of the four bases in DNA. In these studies new molecular structures were discovered, from which the structure of unordered materials can be described. The results are of fundamental importance for our understanding and description of unordered, amorphous materials such as glass. The new results were described in the leading international journal Science. STM studies of other DNA bases have also been pursued and published in Journal of the American Chemical Society.

Synthesis of DNA base derivatives

In extension of the project described above we have prepared a series of rigid organic molecules containing DNA bases in the terminal positions. The syntheses are based on a new synthetic methodology that was also developed at the center. The self-assembly of these structures is now being studied.

An electrochemical biosensor for Theophylline

Theophyllin is an efficient and general drug against asthma, but its application is hampered by a narrow blood concentration window of its application. The serum concentration must be monitored carefully to avoid serious side-effects. We have developed the first electrochemical sensor based on an RNA aptamer. Aptamers are developed to recognize and bind to specific molecules with high selectivity. The developed sensor can monitor theophylline concentrations in buffers and serum with high sensitivity and selectivity. The results have been published in Journal of the American Chemical Society.

First CDNA Minisymposium on DNA Nanotechnology

On August 16 CDNA arranged a mini-symposium on DNA Nanotechnology with speakers from Germany, USA and Denmark. The arrangement was attended by more than 100 participants from all of parts of Denmark.

Prices for CDNA scientists in Aarhus

Professor Jørgen Kjems received Danmarks Naturvidenskabelige Akademis Industrial prize, Professor Flemming Besenbacher has received the Bird, Stewart and Lightfoot Lectureship prize, and Professor Kurt Gothelf has received the Knud Lind Larsen prize.