Example of the light triggered silver nanoparticle formation using salmon sperm DNA templates, which were integrated in a memory device design. Photo: CFN, Dr. Ljiljana Fruk |
In
order to find a method for more cost-effective data storage, a group of
researchers from the DFG-Center for Functional Nanostructures (CFN) at
the Karlsruhe Institute of Technology (KIT) in Germany and the National
Tsing Hua University in Taiwan have created a DNA-based
“write-once-read-many-times” (WORM) memory device.
The
device consists of a thin film of salmon DNA, which has been embedded
with nano-sized particles of silver and then sandwiched between two
electrodes. Ultraviolet light is used to encode information. The concept
is published in Applied Physics Letters.
The
collaboration on these devices started more than a year ago, and was a
productive cross-field/cross-country endeavor. Dr. Ljiljana Fruk heads
an interdisciplinary research group concerned with DNA nanotechnology,
biofunctionalization and light triggered nanodevice design and was
involved in the development of the light triggered, DNA templated
nanoparticle production and its characterization. Dr. Yu-Chueh Hung’s
group on the other side used this knowledge to optimize the process and
design the functional memory device. The transmission electron
microscope (TEM) images of the nanoparticles in the DNA were obtained in
turn by the Nanostructure Service Laboratory in the CFN.
As
described in the article, shining UV light on the system causes the
silver atoms to cluster into nano-sized particles. These particles
provide the platform for the data encoding. The device is able to hold
charge under a low current, which corresponds to the off-state. Under a
high electrical field the charges pass through the device, which then
corresponds to the on-state the device.
The
team in Taiwan found that once the system had been turned on, it stayed
on; changing the voltage across the electrodes did not change the
system’s conductivity. This means that information can be written to the
device but not overwritten. Once written, the device appears to retain
that information indefinitely. The researchers report that the
material’s conductivity did not change significantly during nearly 30
hours of tracking.
The
authors expect the technique to be useful in the design of optical
storage devices and suggest that it may have plasmonic applications as
well. This work combines new advances in DNA nanotechnology with
conventional polymer fabrication platform to realize novel DNA-based
organic devices. It demonstrates new possibilities to fabricate novel,
cheaper and bio friendly devices by integrating and merging several
fields of interest.
Photoinduced write-once read-many-times memory device based on DNA biopolymer nanocomposite
