Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Carbon nanotubes found to fluoresce

30.07.2002


Optical properties could prove useful in biomedical, nanoelectronic applications

Add fluorescence to the growing list of unique physical properties associated with carbon nanotubes -- the ultrasmall, ultrastrong wunderkind of the fullerene family of carbon molecules.

In research detailed in the current issue of Science magazine, a team of Rice University chemists led by fullerene discoverer and Nobel laureate Richard Smalley describes the first observations of fluorescence in carbon nanotubes. Fluorescence occurs when a substance absorbs one wavelength of light and emits a different wavelength in response. The Rice experiments, conducted by Smalley’s group and the photophysics research team of chemist R. Bruce Weisman, found that nanotubes absorbed and gave off light in the near-infrared spectrum, which could prove useful in biomedical and nanoelectronics applications.



"Some of the most sophisticated biomedical tests today -- such as MRI exams -- cannot be performed in a doctor’s office because the equipment too large and too expensive to operate," said Smalley, University Professor at Rice. "Because nothing in the human body fluoresces in the near-infrared spectrum, and human tissue is fairly transparent at that spectrum, one can envision a test apparatus based on this technology that would be as inexpensive and simple to use as ultrasound."

Optical biosensors based on nanotubes could also be targeted to seek out specific targets within the body, such as tumor cells or inflamed tissues. Targeting would be achieved by wrapping the tubes with a protein that would bind only to the target cells. Since nanotubes fluoresce with a single wavelength of light, and different diameter nanotubes give off different wavelengths, it may be possible to tailor different sizes of tubes to seek specific targets, and thus diagnose multiple maladies in a single test using a cocktail of nanotubes.

Carbon nanotubes are a member of the fullerene family of carbon molecules, a third molecular form of carbon that is distinct from diamond and graphite. The discovery of fullerenes in 1985 earned Smalley a share of the Nobel Prize.

Like all fullerenes, carbon nanotubes are extraordinarily stable and almost impervious to radiation and chemical destruction. They’re small enough to migrate through the walls of cells, conduct electricity as well as copper, conduct heat as well as diamond and are 100 times stronger than steel at one-sixth the weight.

Much of Smalley’s current research involves bridging the gap between "wet" nanotechnology -- the molecular, biochemical machinery of life -- and "dry," insoluble nanomaterials like fullerenes. Toward that end, Smalley’s lab has churned out dozens of varieties of soluble fullerenes by wrapping nanotubes in various polymers, including proteins, starches and DNA.

In the fluorescence experiments, Smalley and Weisman’s teams observed the effect only in nanotubes that were untangled and isolated from neighboring tubes. Researchers bombarded clumps of nanotubes with high-frequency sound waves to separate them, and they encased each individual tube in a molecule of sodium dodecylsulfate in order to isolate it from its neighbors. Fluorescence was observed in both plain and polymer-wrapped nanotubes.

In addition to biomedical applications, the fluorescence research could prove useful in the field of nanoelectronics because it confirms that nanotubes are direct band-gap semiconductors, which means they emit light in a way that could be useful for engineers in the fiber optics industry.


The Rice research team included Michael O’Connell, Sergei Bachilo, Chad Huffman, Valerie Moore, Michael Strano, Erik Haroz, Kristy Rialon, Peter Boul, William Noon, Carter Kittrell, Jianpeng Ma and Robert H. Hauge. The research was funded by the National Science Foundation and the Robert A. Welch Foundation.

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

More articles from Life Sciences:

nachricht Navigational view of the brain thanks to powerful X-rays
18.10.2017 | Georgia Institute of Technology

nachricht Separating methane and CO2 will become more efficient
18.10.2017 | KU Leuven

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Osaka university researchers make the slipperiest surfaces adhesive

18.10.2017 | Materials Sciences

Space radiation won't stop NASA's human exploration

18.10.2017 | Physics and Astronomy

Los Alamos researchers and supercomputers help interpret the latest LIGO findings

18.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>