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 Physics, photosynthesis and solar cells
01.12.2016 | University of California - Riverside

nachricht New process produces hydrogen at much lower temperature
01.12.2016 | Waseda University

All articles from Materials Sciences >>>

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 >>>