Nanoscopic gold spheres can be reversibly bound to DNA strands reversibly bound to DNA strands
How can individual components be assembled into larger functional units? And how can robot arms, for example, be made to "grab" specific nano-objects-and to release them at the right moment?
The field of biotechnology presents interesting approaches to these problems.
Researchers at the University of Dortmund have now developed an elegant method
to link nanoparticles reversibly: they use short DNA strands to cause gold
spheres to aggregate "on demand" and then to separate again, also "on demand".
The "genetic molecule" DNA has already proven itself as a nanoconstruction
material; the specific base pairing of mutually complementary DNA regions puts
this material into a position that promotes organization into defined
A team headed by Christof M. Niemeyer has now used this property of
single DNA strands to link together nanoscopic gold particles. The principle
works as follows: The single strands of DNA with two different sequences, A and
B, are attached to tiny spheres of gold. Free DNA strands are then added as
"glue". These consist of three regions: Region A' is exactly complementary to
DNA A and immediately binds to the A strands on the gold spheres. After A' comes
region B', which is the counterpart to DNA B and thus binds to the B strands on
the gold spheres. In this manner, the gold spheres are linked into small clumps.
The third region of the "glue" DNA, called C', is complementary to neither DNA A
nor DNA B, and thus remains unaffected. This end acts as a kind of "tear-away
strap" when it is time to separate the gold spheres from each other. The "glue
remover" is a single strand of DNA that is exactly complementary to the glue DNA
A'B'C', and so consists of regions A, B, and C. This is added to the mixture,
and as soon as its C end "discovers" the free C' end (the "strap") on the glue
DNA, it binds to it. The entire strip of "glue" then detaches to form a complete
double strand with the glue-dissolving DNA. The gold spheres are thus separated
once again and and revert back to their initial state. Addition of more single
strands of glue DNA, can then reinitiate the aggregation.
"Our concept," says Niemeyer, " could be the basis for the production of
nanomaterials with programmable functions."
Getting the grid prepared for the increased use of renewable energy sources is the goal of the Helmholtz Energy Alliance “Technologies for the Future Power Grid”coordinated by KIT. Helmholtz researchers are developing solutions for a flexible and reliable grid which manages the fluctuating ... more
Dr. Thomas Bieringer (43) has been appointed Managing Director of INVITE GmbH, effective July 1, 2011. The research company works on new production concepts for the “Factory of the Future”. The PhD physicist succeeds Michael Lorenz (47), who had been responsible as Managing Director for the ... more
Bayer Technology Services (BTS) and the Technical University of Dortmund (TU Dortmund) have established the INVITE GmbH research company, which will operate a new research center at Chempark Leverkusen, Germany. Flexible and efficient production concepts that help to conserve resources will ... more