WORLD'S LARGEST DNA ORIGAMI CREATED
Researchers from North
Carolina State University, Duke University and the University of Copenhagen
have created the world's largest DNA origami, which are nanoscale constructions
with applications ranging from biomedical research to nanoelectronics
"These origami
can be customized for use in everything from studying cell behavior to creating
templates for the nanofabrication of electronic components," says Dr. Thom
LaBean, an associate professor of materials science and engineering at NC State
and senior author of a paper describing the work.
DNA origami are
self-assembling biochemical structures that are made up of two types of DNA. To
make DNA origami, researchers begin with a biologically derived strand of DNA
called the scaffold strand. The researchers then design customized synthetic
strands of DNA, called staple strands. Each staple strand is made up of a
specific sequence of bases (adenine, cytosine, thaline and guanine -- the
building blocks of DNA), which is designed to pair with specific subsequences
on the scaffold strand.
The staple strands are
introduced into a solution containing the scaffold strand, and the solution is
then heated and cooled. During this process, each staple strand attaches to
specific sections of the scaffold strand, pulling those sections together and
folding the scaffold strand into a specific shape.
The standard for DNA
origami has long been limited to a scaffold strand that is made up of 7,249
bases, creating structures that measure roughly 70 nanometers (nm) by 90 nm,
though the shapes may vary.
However, the research
team led by LaBean has now created DNA origami consisting of 51,466 bases,
measuring approximately 200 nm by 300 nm.
"We had to do two
things to make this viable," says Dr. Alexandria Marchi, lead author of
the paper and a postdoctoral researcher at Duke. "First we had to develop
a custom scaffold strand that contained 51 kilobases. We did that with the help
of molecular biologist Stanley Brown at the University of Copenhagen.
"Second, in order
to make this economically feasible, we had to find a cost-effective way of
synthesizing staple strands -- because we went from needing 220 staple strands
to needing more than 1,600," Marchi says.
The researchers did
this by using what is essentially a converted inkjet printer to synthesize DNA
directly onto a plastic chip.
"The technique we
used not only creates large DNA origami, but has a fairly uniform output,"
LaBean says. "More than 90 percent of the origami are self-assembling
properly."
The research was
supported by the National Science Foundation under grants CDI-0835794,
OISE-1246799, and EPMD-1231888, and by the University of Copenhagen.
Comments
Post a Comment