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 Engineers develop smart material that changes stiffness when twisted or bent
15.02.2018 | Iowa State University

nachricht Breaking local symmetry: Why water freezes but silica forms a glass
14.02.2018 | Institute of Industrial Science, The University of Tokyo

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

Im Focus: Autonomous 3D scanner supports individual manufacturing processes

Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).

Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Fingerprints of quantum entanglement

16.02.2018 | Information Technology

'Living bandages': NUST MISIS scientists develop biocompatible anti-burn nanofibers

16.02.2018 | Health and Medicine

Hubble sees Neptune's mysterious shrinking storm

16.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>