Tuesday, 23 July 2013

Researchers use DNA origami technique to build nanoantennas with docking sites

Researchers use DNA origami
technique to build nanoantennas
with docking sites
A team of researchers working at
Germany's Technische Universit├Ąt
Braunschweig has succeeded in using
a previously known DNA origami
construction technique to build a
nanoantenna with a docking site. First
published in the journal Science , the
paper written by the team has now
been made publicly available for
open access.
DNA scaffolding has in recent years
been developed to allow for orienting
single molecules in useful ways. One
of those has resulted in the creation
of what is known as DNA origami —
where DNA strands are folded in
certain ways to create three
dimensional nano-sized objects. In
this new effort, the team used the
technique to place two gold particles
astride a protein pillar creating a
hotspot that brightens fluorescent
signals in zeptoliter volumes. The
result is a tall pillar held erect on a
flat surface using DNA strands that
can be used to hold single molecules.
The flat surface was made of a
biotin- binding protein . The pillar (also
made of a protein) is 220 nm long
and 15 nm in diameter. It was held
in place by strands of DNA. Two gold
nanoparticles (80 to 100nm diameter)
were suspended (again by DNA
strands) on each side of the pillar (23
nm apart) and were used as an
antenna to focus light on a hotspot
between them. A fluorescent dye was
placed into that hotspot and was
used as an optically active source—
its purpose was to report the degree
of fluorescent enhancement—which
was the purpose of the antenna.
The antenna the team built
demonstrates one way that DNA
origami is being used to build a
scaffold for holding molecules in
three- dimensional space. The hope is
that it will lead to what is known as
atomically precise manufacturing—
where nano-sized components could
be manufactured in bulk. An antenna
such as the one built in this new
effort, allows for focusing light to a
very small volume allowing for
investigating molecules in a way that
is up to 100 times more precise than
conventional lenses. What's most
interesting about the antenna, of
course, is that it's held together by
DNA strands that have been
"programmed" to spontaneously
wrap themselves around the antenna
in just the right way to hold
everything in place.
The researchers next plan to conduct
experiments to see if DNA origami
structures can also be used to allow
for more precise control of chemical

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