Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Rice finds ’on-off switch’ for buckyball toxicity

27.09.2004


CBEN pioneers method of mitigating nanoparticle toxicity via surface enhancement



Researchers at Rice University’s Center for Biological and Environmental Nanotechnology (CBEN) have demonstrated a simple way to reduce the toxicity of water-soluble buckyballs by a factor of more than ten million. The research will appear in an upcoming issue of the journal Nano Letters, published by the American Chemical Society, the world’s largest scientific society. One of the first toxicological studies of buckyballs, the research was published online by the journal on Sept. 11.

Buckyballs, whose chemical notation is C60, are hollow, soccerball-shaped molecules containing 60 carbon atoms. Their diameter is just one-billionth of a meter, or one nanometer, and their discovery at Rice in 1985 is widely regarded as an early milestone in the field of nanotechnology.


While buckyballs show great promise in applications as diverse as fuel cells, batteries, pharmaceuticals and coatings, some scientists and activists have raised concerns about their potential toxicity to humans and animals.

CBEN’s study is the first cytotoxicity study of human cells exposed to buckyballs. Cytotoxicity refers to toxic effects on individual cells. The study found that even minor alterations to the surface of the buckyballs can dramatically affect how toxic they are to individual cells, and the researchers identified specific alterations that render them much less toxic.

"There are many cases where toxicity is desirable," said Vicki Colvin, CBEN director, professor of chemistry and chemical engineering, and the principal investigator for the research. "For example, we might want particles that kill cancer cells or harmful bacteria. In other cases -- like applications where particles may make their way into the environment -- toxicity is undesirable."

In the study, the researchers exposed two types of human cells to various solutions containing different concentrations of buckyballs. Four types of solutions were tested. One contained tiny clusters of smooth-surfaced buckyballs. In the other three, researcher s modified the buckyballs by attaching other molecules to their sides. Researchers measured how many cells died within 48 hours of exposure to each solution, and they repeated the tests until they found the exposure level for each that resulted in a 50 percent mortality rate.

In general, the greater the degree of surface modification, the lower the toxicity. For example, the undecorated buckyballs showed the highest toxicity -- about 20 parts per billion-- while the least toxic proved to be buckyballs decorated with the largest number of hydroxyl side-groups. To achieve the equivalent level of toxicity as that of bare buckyballs, the researchers had to increase the concentration of these modified buckyballs by 10 million times to more than 5 million parts per billion.

"We’re encouraged to see that controlling the surface properties of buckyballs allows us to dial the level of toxicity up or down, because making those kinds of modifications is something that chemists do every day in university research labs and in industry," Colvin said. "Moreover, we believe the technique can prove useful in tuning the toxicity of other nanoparticles."

The researchers postulate that cell death in the tests occurred via physical disruption of the cell membrane by oxygen radical species generated by the buckyballs. Colvin and her colleagues emphasize that the study only fills in part of the puzzle regarding fullerene toxicity. For example, because cytotoxic studies look only at cells in culture, they don’t tell scientists what happens inside the body, where cellular repair mechanisms, whole-organ and whole-body processes come into play.

"Cytotoxicity should not be confused with a full-fledged toxicological risk assessment," said Kevin Ausman, CBEN executive director and a co-author of the paper. "Risk assessments take into account exposure rates, uptake mechanisms, transport within the body and much more. Most often, cytotoxicity studies are used as indicators of whether more extensive toxicological study is needed. Based on our results we think buckyballs should be studied in more detail, and we’re already working to arrange additional studies."

Jade Boyd | EurekAlert!
Further information:
http://www.rice.edu

More articles from Studies and Analyses:

nachricht The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>