|
DNA holds the
genetic code for all sorts of biological molecules and traits. But University
of Illinois researchers have found that DNA’s code can similarly shape metallic
structures.
The team found
that DNA segments can direct the shape of gold nanoparticles—tiny gold crystals
that have many applications in medicine, electronics, and catalysis. Led by Yi
Lu, the Schenck Professor of Chemistry at the U. of I., the team published its
findings in Angewandte Chemie.
“DNA-encoded
nanoparticle synthesis can provide us a facile but novel way to produce
nanoparticles with predictable shape and properties,” Lu said. “Such a
discovery has potential impacts in bio-nanotechnology and applications in our
everyday lives such as catalysis, sensing, imaging, and medicine.”
Gold
nanoparticles have wide applications in both biology and materials science
thanks to their unique physicochemical properties. Properties of a gold
nanoparticle are largely determined by its shape and size, so it is critical to
be able to tailor the properties of a nanoparticle for a specific application.
“We wondered
whether different combinations of DNA sequences could constitute ‘genetic
codes’ to direct the nanomaterial synthesis in a way similar to their direction
of protein synthesis,” said Zidong Wang, a recent graduate of Lu’s group and the
first author of the paper.
Gold
nanoparticles are made by sewing tiny gold seeds in a solution of gold salt.
Particles grow as gold in the salt solution deposits onto the seeds. Lu’s group
incubated the gold seeds with short segments of DNA before adding the salt
solution, causing the particles to grow into various shapes determined by the
genetic code of the DNA.
The DNA alphabet
comprises four letters: A, T, G, and C. The term genetic code refers to the
sequence of these letters, called bases. The four bases and their combinations
can bind differently with facets of gold nanoseeds and direct the nanoseeds’
growth pathways, resulting in different shapes.
In their experiments,
the researchers found that strands of repeating A’s produced rough, round gold
particles; T’s, stars; C’s, round, flat discs; G’s, hexagons. Then the group
tested DNA strands that were a combination of two bases, for example, 10 T’s
and 20 A’s. They found that many of the bases compete with each other resulting
in intermediate shapes, although A dominates over T.
Next, the
researchers plan to investigate exactly how DNA codes direct nanoparticle
growth. They also plan to apply their method to synthesize other types of
nanomaterials with novel applications.
