Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > DNA-wrapped carbon nanotubes serve as sensors in living cells

Abstract:
Discovery opens the door to new types of optical sensors and biomarkers that exploit the unique properties of nanoparticles in living systems

DNA-wrapped carbon nanotubes serve as sensors in living cells

Champaign, IL | Posted on January 27, 2006

Single-walled carbon nanotubes wrapped with DNA can be placed inside living cells and detect trace amounts of harmful contaminants using near infrared light, report researchers at the University of Illinois at Urbana-Champaign. Their discovery opens the door to new types of optical sensors and biomarkers that exploit the unique properties of nanoparticles in living systems.

"This is the first nanotube-based sensor that can detect analytes at the subcellular level," said Michael Strano, a professor of chemical and biomolecular engineering at Illinois and corresponding author of a paper to appear in the Jan. 27 issue of the journal Science. "We also show for the first time that a subtle rearrangement of an adsorbed biomolecule can be directly detected by a carbon nanotube."

At the heart of the new detection system is the transition of DNA secondary structure from the native, right-handed "B" form to the alternate, left-handed "Z" form.

"We found that the thermodynamics that drive the switching back and forth between these two forms of DNA structure would modulate the electronic structure and optical emission of the carbon nanotube," said Strano, who is also a researcher at the Beckman Institute for Advanced Science and Technology and at the university's Micro and Nanotechnology Laboratory.

To make their sensors, the researchers begin by wrapping a piece of double-stranded DNA around the surface of a single-walled carbon nanotube, in much the same fashion as a telephone cord wraps around a pencil. The DNA starts out wrapping around the nanotube with a certain shape that is defined by the negative charges along its backbone.

When the DNA is exposed to ions of certain atoms - such as calcium, mercury and sodium - the negative charges become neutralized and the DNA changes shape in a similar manner to its natural shape-shift from the B form to Z form. This reduces the surface area covered by the DNA, perturbing the electronic structure and shifting the nanotube's natural, near infrared fluorescence to a lower energy.

"The change in emission energy indicates how many ions bind to the DNA," said graduate student Daniel Heller, lead author of the Science paper. "Removing the ions will return the emission energy to its initial value and flip the DNA back to the starting form, making the process reversible and reusable."

The researchers demonstrated the viability of their measurement technique by detecting low concentrations of mercury ions in whole blood, opaque solutions, and living mammalian cells and tissues - examples where optical sensing is usually poor or ineffective. Because the signal is in the near infrared, a property unique to only a handful of materials, it is not obscured by the natural fluorescence of polymers and living tissues.

"The nanotube surface acts as the sensor by detecting the shape change of the DNA as it responds to the presence of target ions," Heller said.

Co-authors of the paper with Strano and Heller are graduate student Esther Jeng and undergraduate students Tsun-Kwan Yeung, Brittany Martinez, Anthonie Moll and Joseph Gastala. The work was funded by the National Science Foundation.

####
Contact:
James E. Kloeppel
Physical Sciences Editor
217-244-1073
kloeppel@uiuc.edu

Copyright University of Illinois at Urbana-Champaign

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

Possible Futures

Nanofiltration Membrane Market 2015 - Global Industry Survey, Analysis, Size, Share, Outlook and Forecast to 2020 July 31st, 2015

Nanozirconia Market 2015 - Global Industry Survey, Analysis, Size, Share, Outlook and Forecast to 2020 July 31st, 2015

Self-Healing Nano Anti-rust Coatings Market 2015 - Global Industry Survey, Analysis, Size, Share, Outlook and Forecast to 2020 July 31st, 2015

Nano Spray Instrument Market 2015 - Global Industry Survey, Analysis, Size, Share, Outlook and Forecast to 2020 July 31st, 2015

Nanotubes/Buckyballs/Fullerenes

Self-assembling, biomimetic membranes may aid water filtration August 1st, 2015

Controlling Dynamic Behavior of Carbon Nanosheets in Structures Made Possible July 30th, 2015

March 2016; 6th Int'l Conference on Nanostructures in Iran July 29th, 2015

Short wavelength plasmons observed in nanotubes: Berkeley Lab researchers create Ludinger liquid plasmons in metallic SWNTs July 28th, 2015

Nanomedicine

Gold-diamond nanodevice for hyperlocalised cancer therapy: Gold nanorods can be used as remote controlled nanoheaters delivering the right amount of thermal treatment to cancer cells, thanks to diamond nanocrystals used as temperature sensors August 1st, 2015

Heating and cooling with light leads to ultrafast DNA diagnostics July 31st, 2015

Take a trip through the brain July 30th, 2015

Sol-gel capacitor dielectric offers record-high energy storage July 30th, 2015

Sensors

Gold-diamond nanodevice for hyperlocalised cancer therapy: Gold nanorods can be used as remote controlled nanoheaters delivering the right amount of thermal treatment to cancer cells, thanks to diamond nanocrystals used as temperature sensors August 1st, 2015

Advances and Applications in Biosensing, Sensor Power, and Sensor R&D to be Covered at Sensors Global Summit August 1st, 2015

Controlling Dynamic Behavior of Carbon Nanosheets in Structures Made Possible July 30th, 2015

Non-Enzyme Sensor Determines Level of Blood Sugar July 29th, 2015

Announcements

Self-assembling, biomimetic membranes may aid water filtration August 1st, 2015

Transparent, electrically conductive network of encapsulated silver nanowires: A novel electrode for optoelectronics August 1st, 2015

Harris & Harris Group Portfolio Company, HZO, Announces Partnerships with Dell and Motorola August 1st, 2015

Advances and Applications in Biosensing, Sensor Power, and Sensor R&D to be Covered at Sensors Global Summit August 1st, 2015

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