Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Graphene-DNA biosensor selective, simple to create

An illustration of how fluorescent-tagged DNA interacts with functionalized graphene. Both single-stranded DNA (A) and double-stranded DNA (B) are adsorbed onto a graphene surface, but the interaction is stronger with ssDNA, causing the fluorescence on the ssDNA to darken more. C) A complimentary DNA nears the ssDNA and causes the adsorbed ssDNA to detach from the graphene surface. D) DNA adsorbed onto graphene is protected from being broken down
An illustration of how fluorescent-tagged DNA interacts with functionalized graphene. Both single-stranded DNA (A) and double-stranded DNA (B) are adsorbed onto a graphene surface, but the interaction is stronger with ssDNA, causing the fluorescence on the ssDNA to darken more. C) A complimentary DNA nears the ssDNA and causes the adsorbed ssDNA to detach from the graphene surface. D) DNA adsorbed onto graphene is protected from being broken down

Abstract:
Nanostructure could help diagnose disease, facilitate gene therapy, more

Graphene-DNA biosensor selective, simple to create

Richland, WA | Posted on May 15th, 2010

Graphene and DNA can combine to create a stable and accurate biosensor, reports a study published in the nanotechnology journal Small. The tiny biosensor might eventually help doctors and researchers better understand and diagnose disease.

Scientists at the Department of Energy's Pacific Northwest National Laboratory and Princeton University showed that single-stranded DNA strongly interacts with graphene, a nanomaterial made of sheets of carbon atoms just a single atom thick. They also found that graphene protects DNA from being broken down by enzymes similar to those found in body fluids - a characteristic that should make graphene-DNA biosensors highly durable.

"Graphene is of great interest because it has several unique characteristics, including being easy and relatively inexpensive to make," said PNNL chemist Yuehe Lin, the paper's corresponding author. "But very few had systematically explored how graphene interacted with DNA using multiple spectroscopic techniques until we took a look. We found they make quite the pair."

Scientists have been exploring the potential of nanotechnology - or tiny materials that are just one billionth of a meter in size - for several decades. A growing number of scientists are focusing on graphene because it is superconductive, is exceptionally strong and has a large surface area. It's also easier to make and use than other nanomaterials, such as carbon nanotubes. Nanotechnology could help create new drugs, deliver medicine and develop disease-detecting biosensors.

A graphene-DNA biosensor would detect diseases by fishing for molecules involved in disease. Like stringing a worm on a hook, scientists would place DNA from a gene that's known to contribute to a disease's development onto a piece of graphene. The researchers would then dip the biosensor hook into treated blood, saliva or another bodily fluid. If DNA from the disease-causing gene is in the fluid and takes the bait, the biosensor gives off a signal that scientists can detect.

The double-stranded nature of the DNA in our genes makes this fishing scheme possible. Normal double-stranded DNA looks like a twisted ladder. But single-stranded DNA looks like a comb: it's made up of a sequence of DNA letters, or bases, that stick up from the backbone and that look for another base to pair up with. When complementary sequences on single-stranded DNA meet, the bases form the rungs of the twisted ladder.

To design DNA-graphene biosensors, scientists need to understand how DNA and graphene interact. Lin and colleagues, including lead author and then-PNNL post-doctoral researcher Zhiwen Tang, attached a fluorescent molecule to DNA that glows when DNA floats freely to follow the DNA in test tubes. Next, they mixed the glowing DNA and graphene. Single-stranded DNA dimmed when it came in contact with graphene. But the brightness of double-stranded DNA decreased only slightly under the same conditions. Further analysis with several spectroscopy tests showed that graphene's interaction with single-stranded DNA is much stronger than with its double-stranded cousin. The tests also suggested that graphene altered single-stranded DNA's structure.

To find out if single-stranded DNA could be coaxed off the graphene by making it double-stranded, the researchers added plain, single-stranded DNA that had a complementary sequence of DNA bases. The original single-stranded DNA shined anew. This indicated the original single strand of DNA had combined with the added DNA strand and formed a new molecule that detached from graphene's surface.

The scientists then tested how picky the single-stranded DNA on the graphene was about partners. They placed the graphene-DNA biosensors into two different test tubes. In one, they added a complementary DNA strand with bases that were a perfect match to the DNA already attached to the graphene. In the other, they placed a complementary DNA strand that had one base that didn't pair up with the original DNA strand on the graphene surface.

Both gave off more light after the complementary DNA was introduced. But light from the tube with the perfectly matched DNA strands was two times brighter than from the tube with the slightly mismatched DNA strands. The ability to identify whether a target DNA strand has been found within one base match - called high specificity - should make graphene-DNA biosensors more accurate than other, conventional linear DNA biosensors, the scientists wrote.

Graphene also helps make DNA durable, the scientists learned. They placed two kinds of single-stranded DNA - one that was attached to graphene, and another that was free floating - in test tubes. They added DNAse - an enzyme that chews up DNA - to both and found that the free DNA strands were broken down, while the graphene-DNA nanostructures remained intact for at least 60 minutes. The scientists suggested this protection could make DNA-graphene platforms that are well suited for imaging and gene delivery in patients.

"The simple design and tremendous durability of graphene-DNA biosensors make diagnosing life-threatening diseases with them a possibility," Lin said. "Now my colleagues and I will look to see if graphene's ability to protect DNA against enzymes could help DNA-graphene structures deliver drugs to diseased cells or even help with in gene therapy."

Princeton University provided the graphene and PNNL's Transformational Materials Science Initiative paid for this study. Some of the research was conducted at EMSL, the Environmental Molecular Sciences Laboratory, a national scientific user facility located at PNNL.

REFERENCE: Zhiwen Tang, Hong Wu, John R. Cort, Garry W. Buchko, Youyu Zhang, Yuyan Shao, Ilhan A. Aksay, Jun Liu, Yuehe Lin. "The Constraint of DNA on Functionalized Graphene Improves Its Biostability and Specificity" Small. Published online May 11, 2010. www3.interscience.wiley.com/cgi-bin/fulltext/123430457/PDFSTART. To be published in the June 7, 2010 print edition.

####

About Pacific Northwest National Laboratory
Pacific Northwest National Laboratory is a Department of Energy Office of Science national laboratory where interdisciplinary teams advance science and technology and deliver solutions to America's most intractable problems in energy, national security and the environment. PNNL employs 4,700 staff, has an annual budget of nearly $1.1 billion, and has been managed by Ohio-based Battelle since the lab's inception in 1965.

EMSL, the Environmental Molecular Sciences Laboratory, is a national scientific user facility sponsored by the Department of Energy's Office of Science, Biological and Environmental Research program that is located at Pacific Northwest National Laboratory. EMSL offers an open, collaborative environment for scientific discovery to researchers around the world. EMSL's technical experts and suite of custom and advanced instruments are unmatched. Its integrated computational and experimental capabilities enable researchers to realize fundamental scientific insights and create new technologies.

For more information, please click here

Contacts:
Frances White
PNNL
(509) 375-6904

Copyright © Pacific Northwest National Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

Possible Futures

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

Nanotubes/Buckyballs/Fullerenes/Nanorods

How to draw electricity from the bloodstream: A one-dimensional fluidic nanogenerator with a high power-conversion efficiency September 11th, 2017

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

Regulation of two-dimensional nanomaterials: New driving force for lithium-ion batteries July 26th, 2017

Killing cancer in the heat of the moment: A new method efficiently transfers genes into cells, then activates them with light. This could lead to gene therapies for cancers July 9th, 2017

Nanomedicine

Do titanium dioxide particles from orthopedic implants disrupt bone repair? September 16th, 2017

Arrowhead Hosts Investor & Analyst R&D Day to Introduce TRiM(TM) Platform and Lead RNAi-based Drug Candidates September 14th, 2017

Graphene based terahertz absorbers: Printable graphene inks enable ultrafast lasers in the terahertz range September 13th, 2017

Applications for the nanomedTAB are open until September 18th, 2017 September 13th, 2017

Sensors

Leti Develops Proof of Concept to Test Wireless Systems in Aircraft: Will Present Results of Joint Project at AeroTech Conference And Exhibition in Fort Worth, Texas, Sept. 26-28 September 20th, 2017

Research shows how DNA molecules cross nanopores: Study could inform biosensors, manufacturing, and more September 5th, 2017

Leti and Partners in PiezoMAT Project Develop New Fingerprint Technology for Highly Reliable Security and ID Applications: Ultra-high Resolution Pressure Sensing Uses Matrices of Vertical Piezoelectric Nanowire To Reconstruct the Smallest Features of Human Fingerprints September 5th, 2017

New results reveal high tunability of 2-D material: Berkeley Lab-led team also provides most precise band gap measurement yet for hotly studied monolayer moly sulfide August 26th, 2017

Announcements

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

Nanobiotechnology

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Do titanium dioxide particles from orthopedic implants disrupt bone repair? September 16th, 2017

Applications for the nanomedTAB are open until September 18th, 2017 September 13th, 2017

Magnetic cellular 'Legos' for the regenerative medicine of the future September 12th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project