Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

It All Depends on the Length

21.01.2013
Chemical functionalization of ‘toxic’ long carbon nanotubes reduces their effective length and alleviates asbestos-like pathogenicity

Carbon nanotubes resemble asbestos fibers in their form. Unfortunately, long, pure nanotubes also seem to have asbestos-like pathogenicity.



In the journal Angewandte Chemie, a European research team has now reported that chemical modifications, for example with tri(ethylene glycol), can alleviate this problem if the modification makes their surface more water-friendly and reduces the effective length of the tubes.

Due to their unique physical, chemical, and electronic properties, carbon nanotubes have become one of the most popular nanomaterials. They are used in electronics, for reinforcing plastics, and in biomedicine as nanotransporters to carry drugs into cells. For many of these applications, particularly in the area of biology, it is necessary to chemically alter the tubes by attaching molecules to their surfaces.

However, the industrial production of carbon nanotubes could bring health risks with it. Studies have shown that multi-walled nanotubes that are more than 20 µm long act like asbestos fibers, causing inflammation followed by granulomas—inflammation-induced knotlike tissue growths. This occurs because the macrophages of our immune system cannot absorb and remove the long fibers. Shorter nanotubes and those with certain surface modifications have now been shown to alleviate toxicity.

A team led by Maurizio Prato, Alberto Bianco, and Kostas Kostarelos wanted to determine what role the chemical modifications have in resolving the toxic risk from the tubes. The scientists from University College London (UK), the CNRS in Strasbourg (France), and the University of Trieste (Italy) attached either hydrocarbon chains or tri(ethylene glycol) chains as side-groups on multi-walled carbon nanotubes and compared their effects to those of unmodified tubes. The results show that the unmodified nanotubes and those with hydrocarbon chains lead to asbestos-like inflammation and granulomas in mice.

However, the carbon nanotubes with tri(ethylene glycol) chains do not.
The difference seems to be a question of aggregation/disaggregation that influences the length of the bundles: As shown by images from transmission electron and atomic force microscopies, the effective length of the tubes is reduced during the reaction that introduces the tri(ethylene glycol) chains.

The researchers believe that the modification with the tri(ethylene glycol) chain breaks apart the tubes from each other so that they interact in the body as shorter, much more hydrophilic individual fibers, whereas both the unmodified tubes and those with apolar hydrocarbons on their surfaces interact with tissue as longer bundles of individual nanotubes.

The researchers conclude that only those modifications that lead to a disentangling of the bundles can alleviate the toxicological problems.

About the Author
Alberto Bianco is Research Director at the French National Center for Scientific Research (CNRS). His research interests focus on the design and development of chemically functionalized carbon nanomaterials for biomedical applications.

Author: Alberto Bianco, CNRS, Institut de Biologie Moléculaire et Cellulaire, Strasbourg (France), mailto:a.bianco@ibmc-cnrs.unistra.fr

Title: Asbestos-like Pathogenicity of Long Carbon Nanotubes Can be Alleviated by Chemical Functionalization

Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201207664

Alberto Bianco | Angewandte Chemie
Further information:
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht Small but ver­sat­ile; key play­ers in the mar­ine ni­tro­gen cycle can util­ize cy­anate and urea
10.12.2018 | Max-Planck-Institut für Marine Mikrobiologie

nachricht Carnegie Mellon researchers probe hydrogen bonds using new technique
10.12.2018 | Carnegie Mellon University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

Im Focus: A bit of a stretch... material that thickens as it's pulled

Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.

Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...

Im Focus: The force of the vacuum

Scientists from the Theory Department of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science (CFEL) in Hamburg have shown through theoretical calculations and computer simulations that the force between electrons and lattice distortions in an atomically thin two-dimensional superconductor can be controlled with virtual photons. This could aid the development of new superconductors for energy-saving devices and many other technical applications.

The vacuum is not empty. It may sound like magic to laypeople but it has occupied physicists since the birth of quantum mechanics.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

 
Latest News

Small but ver­sat­ile; key play­ers in the mar­ine ni­tro­gen cycle can util­ize cy­anate and urea

10.12.2018 | Life Sciences

New method gives microscope a boost in resolution

10.12.2018 | Physics and Astronomy

Carnegie Mellon researchers probe hydrogen bonds using new technique

10.12.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>