Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

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

Air Force’s 30-year plan seeks 'strategic agility' August 1st, 2014

IBM Announces $3 Billion Research Initiative to Tackle Chip Grand Challenges for Cloud and Big Data Systems: Scientists and engineers to push limits of silicon technology to 7 nanometers and below and create post-silicon future July 10th, 2014

Virus structure inspires novel understanding of onion-like carbon nanoparticles April 10th, 2014

Local girl does good March 22nd, 2014

Nanotubes/Buckyballs

Nanoparticles Accumulate Quickly in Wetland Sediment: Aquatic food chains might be harmed by molecules "piggybacking" on carbon nanoparticles October 1st, 2014

Elsevier Publishes New Content on Graphene and Materials Science: Books Discuss Properties and Emerging Applications of Carbon Nanotubes, Graphene and Nanomaterials September 25th, 2014

Future flexible electronics based on carbon nanotubes: Study in Applied Physics Letters show how to improve nanotube transistor and circuit performance with fluoropolymers September 23rd, 2014

Nanotubes help healing hearts keep the beat: Rice University, Texas Children’s Hospital patch for defects enhances electrical connections between cells September 23rd, 2014

Nanomedicine

'Stealth' nanoparticles could improve cancer vaccines October 1st, 2014

New Absorber Will Lead to Better Biosensor: Biosensors are more sensitive and able to detect smaller changes in the environment October 1st, 2014

Ad-REIC vaccine: A magic bullet for cancer treatment September 30th, 2014

New Topical Hemostatic Agent: Neutral Self-Assembling Peptide Hydrogel September 30th, 2014

Sensors

New Absorber Will Lead to Better Biosensor: Biosensors are more sensitive and able to detect smaller changes in the environment October 1st, 2014

Graphene and Amaranthus Superparamagnets: Breakthrough nanoparticles discovery of Indian researcher September 23rd, 2014

IEEE International Electron Devices Meeting To Celebrate 60th Anniversary as The Leading Technical Conference for Advanced Semiconductor Devices September 18th, 2014

Biosensors Get a Boost from Graphene Partnership: $5 Million Investment Supports Dozens of Jobs and Development of 300mm Fabrication Process and Wafer Transfer Facility September 18th, 2014

Announcements

'Stealth' nanoparticles could improve cancer vaccines October 1st, 2014

Stressed Out: Research Sheds New Light on Why Rechargeable Batteries Fail October 1st, 2014

New Absorber Will Lead to Better Biosensor: Biosensors are more sensitive and able to detect smaller changes in the environment October 1st, 2014

Graphene chips are close to significant commercialization October 1st, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE