Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Purdue research suggests ’nanotubes’ could make better brain probes

08.01.2004


Purdue University researchers have shown that extremely thin carbon fibers called "nanotubes" might be used to create brain probes and implants to study and treat neurological damage and disorders.



Probes made of silicon currently are used to study brain function and disease but may one day be used to apply electrical signals that restore damaged areas of the brain. A major drawback to these probes, however, is that they cause the body to produce scar tissue that eventually accumulates and prevents the devices from making good electrical contact with brain cells called neurons, said Thomas Webster, an assistant professor of biomedical engineering.

New findings showed that the nanotubes not only caused less scar tissue but also stimulated neurons to grow 60 percent more fingerlike extensions, called neurites, which are needed to regenerate brain activity in damaged regions, Webster said.


The findings are detailed in a paper appearing this month in the journal Nanotechnology, published by the Institute of Physics in the United Kingdom. The paper was written by Webster, Purdue doctoral students Janice L. McKenzie and Rachel L. Price, former postdoctoral fellow Jeremiah U. Ejiofor and visiting undergraduate student Michael C. Waid from the University of Nebraska.

The nanotubes were specially designed so that their surfaces contained tiny bumps measured in nanometers, or billionths of a meter. Conventional silicon probes do not contain the nanometer-scale surface features, causing the body to regard them as foreign invaders and surround them with scar tissue. Because the nanometer-scale features mimic those found on the surfaces of natural brain proteins and tissues, the nanotubes induce the formation of less scar tissue.

The scar tissue is produced by cells called astrocytes, which attach to the probes. The Purdue researchers discovered that about half as many astrocytes attach to the nanofibers compared to nanotubes that don’t have the small features.

"These astrocytes can’t make scar tissue unless they can adhere to the probe," Webster said. "Fewer astrocytes adhering to the nanotubes means less scar tissue will be produced."

The Purdue researchers pressed numerous nanofibers together to form discs and placed them in petri plates. Then the petri plates were filled with a liquid suspension of astrocytes. After one hour the nanotube disks were washed and a microscope was used to count how many of the dyed astrocytes washed out of the suspension, which enabled the researchers to calculate how many astrocytes stuck to the nanotubes. About 400 astrocytes per square centimeter adhered to the nanotubes containing the small surface features, compared to about 800 for nanotubes not containing the small surface features. The researchers repeated the experiment while leaving the nanotubes in the cell suspension for two weeks, yielding similar results.

When the nanotubes were placed in a suspension with neurons, the brain cells sprouted about five neurites, compared with the usual three neurites formed in suspensions with nanotubes that didn’t have the small surface features.

Researchers plan to make brain probes and implants out of a mixture of plastics and nanotubes. The findings demonstrated that progressively fewer astrocytes attached to this mixture as the concentration of nanotubes was increased and the concentration of plastics was decreased.

"That means if you increase the percentage of carbon nanofibers you can decrease the amount of scar tissue that might form around these electrodes," Webster said.

The nanometer-scale bumps mimic features found on the surface of a brain protein called laminin.

"Neurons recognize parts of that protein and latch onto it," Webster said.

The crucifix-shaped protein then helps neurons sprout neurites, while suppressing the formation of scar tissue.

The tube-shaped molecules of carbon have unusual properties that make them especially promising for these and other applications. Researchers theorize that electrons might flow more efficiently over extremely thin nanotubes than they do over conventional circuits, possibly enabling scientists to create better brain probes as well as non-silicon-based transistors and more powerful, compact computers.

"Nano" is a prefix meaning one-billionth, so a nanometer is one-billionth of a meter, or roughly the length of 10 hydrogen atoms strung together. The nanotubes were about 100 nanometers wide, or roughly 1,000 times as thin as a human hair.

The research is funded by the National Science Foundation.

Webster also plans to test the effectiveness of silicon that contains the same sort of nanometer-scale features as the nanotubes, which could increase the performance of silicon probes and implants. In work with Spire Biomedical Inc. (Nasdaq:SPIR) in Bedford, Mass., Purdue researchers will analyze silicon that contains numerous pores, unlike conventional silicon, which has no such porous features. That research is funded by the National Science Foundation and the federal Small Business Innovation Research Program.

Writer: Emil Venere, (765) 494-4709, venere@purdue.edu
Source: Thomas Webster, (765) 496-7516, twebster@purdue.edu
Purdue News Service: (765) 494-2096; purduenews@purdue.edu

Note to Journalists: An electronic copy of the research paper is available from Emil Venere, (765) 494-4709, venere@purdue.edu

Emil Venere | Purdue News
Further information:
http://news.uns.purdue.edu/html4ever/2004/040107.Webster.neural.html

More articles from Materials Sciences:

nachricht Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern
20.07.2018 | Princeton University

nachricht Relax, just break it
20.07.2018 | DOE/Argonne National Laboratory

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>