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 Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

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: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>