Atomically precise control
To test the assumption that discrete DNA objects could be assembled as designed with subnanometer precision, TUM biophysicists collaborated with scientists at the MRC Laboratory of Molecular Biology in Cambridge, UK. They produced a relatively large, three-dimensional DNA-based structure, asymmetrical to help determine the orientation, and incorporating distinctive design motifs.
Subnanometer-resolution imaging with low-temperature electron microscopy enabled the researchers to map the object which comprises more than 460,000 atoms with subnanometer-scale detail. Because the object incorporates, in effect, a whole library of different design elements, it will also serve as a resource for further study. The results, reported in Proceedings of the National Academy of Sciences, not only demonstrate atomically precise assembly, but also show that such structures, formerly thought to be jelly-like and flexible, are rigid enough to be probed by electron microscopy.
Fast processing, near-100% yields
In contrast, DNA objects with 19 different designs including plate-like, gear-like, and brick-like shapes were used for a second series of experiments at TUM, reported in the latest issue of Science. Here the researchers' main focus was on the dynamics of DNA folding and unfolding. The usual self-assembly process is often described as a "one-pot reaction": Strands of DNA that will serve as the template, instructions, and building material for a designed object are placed together at a relatively high temperature where they will remain separate; the temperature is gradually lowered, and somewhere along the line the DNA strands zip together to form the d
|Contact: Patrick Regan|
Technische Universitaet Muenchen