Featured Research

from universities, journals, and other organizations

Better brain implant: Slim electrode cozies up to single neurons

Date:
November 11, 2012
Source:
University of Michigan
Summary:
A thin, flexible electrode is 10 times smaller than the nearest competition and could make long-term measurements of neural activity practical at last.

An artist's rendering of individual neurons. A new electrode developed at the University of Michigan can focus on the electrical signals of just one neuron. It may help researchers understand how electrical signals move through neural networks in the brain. Because this electrode is so small and unobtrusive, it may be able to stay in the brain for long periods without upsetting the immune system, perhaps picking up signals to send to prosthetic limbs.
Credit: Takashi Kozai

A thin, flexible electrode developed at the University of Michigan is 10 times smaller than the nearest competition and could make long-term measurements of neural activity practical at last.

This kind of technology could eventually be used to send signals to prosthetic limbs, overcoming inflammation larger electrodes cause that damages both the brain and the electrodes.

The main problem that neurons have with electrodes is that they make terrible neighbors. In addition to being enormous compared to the neurons, they are stiff and tend to rub nearby cells the wrong way. The resident immune cells spot the foreigner and attack, inflaming the brain tissue and blocking communication between the electrode and the cells.

The new electrode developed by the teams of Daryl Kipke, a professor of biomedical engineering, Joerg Lahann, a professor of chemical engineering, and Nicholas Kotov, the Joseph B. and Florence V. Cejka Professor of Engineering, is unobtrusive and even friendly in comparison. It is a thread of highly conductive carbon fiber, coated in plastic to block out signals from other neurons. The conductive gel pad at the end cozies up to soft cell membranes, and that close connection means the signals from brain cells come in much clearer.

"It's a huge step forward," Kotov said. "This electrode is about seven microns in diameter, or 0.007 millimeters, and its closest competitor is about 25 to 100 microns."

The gel even speaks the cell's language, he said. Electrical impulses travel through the brain by movements of ions, or atoms with electric charges, and the signals move through the gel in the same way. On the other side, the carbon fiber responds to the ions by moving electrons, effectively translating the brain's signal into the language of electronic devices.

To demonstrate how well the electrode listens in on real neurons, Kipke's team implanted it into the brains of rats. The electrode's narrow profile allows it to focus on just one neuron, and the team saw this in the sharp electrical signals coming through the fiber. They weren't getting a muddle of multiple neurons in conversation. In addition to picking up specific signals to send to prosthetics, listening to single neurons could help tease out many of the brain's big puzzles.

"How neurons are communicating with each other? What are the pathways for information processing in the brain? These are the questions that can be answered in the future with this kind of technique," Kotov said.

"Because these devices are so small, we can combine them with emerging optical techniques to visually observe what the cells are doing in the brain while listening to their electrical signals," said Takashi Kozai, who led the project as a student in Kipke's lab and has since earned his Ph.D. "This will unlock new understanding of how the brain works on the cellular and network level."

Kipke stressed that the electrode that the team tested is not a clinical trial-ready device, but it shows that efforts to shrink electrodes toward the size of brain cells are paying off.

"The results strongly suggest that creating feasible electrode arrays at these small dimensions is a viable path forward for making longer-lasting devices," he said.

In order to listen to a neuron for long, or help people control a prosthetic as they do a natural limb, the electrodes need to be able to survive for years in the brain without doing significant damage. With only six weeks of testing, the team couldn't say for sure how the electrode would fare in the long term, but the results were promising.

"Typically, we saw a peak in immune response at two weeks, then by three weeks it subsided, and by six weeks it had already stabilized," Kotov said. "That stabilization is the important observation."

The rat's neurons and immune system got used to the electrodes, suggesting that the electronic invaders might be able to stay for the long term.

While we won't see bionic arms or Iron Man-style suits on the market next year, Kipke is optimistic that prosthetic devices could start linking up with the brain in a decade or so.

"The surrounding work of developing very fine robotic control and clinical training protocols -- that work is progressing along its own trajectory," Kipke said.

Kipke, director of the Center for Neural Communication Technology, is a professor of biomedical engineering. Kotov, the Joseph B. and Florence V. Cejka Professor of Engineering, is a professor of biomedical engineering, chemical engineering, biomaterials science and engineering, and macromolecular science and engineering. Lahann, director of the Biointerfaces Institute, is a professor of chemical engineering, materials science and engineering, biomedical engineering, and macromolecular science and engineering.


Story Source:

The above story is based on materials provided by University of Michigan. Note: Materials may be edited for content and length.


Journal Reference:

  1. Takashi D. Yoshida Kozai, Nicholas B. Langhals, Paras R. Patel, Xiaopei Deng, Huanan Zhang, Karen L. Smith, Joerg Lahann, Nicholas A. Kotov, Daryl R. Kipke. Ultrasmall implantable composite microelectrodes with bioactive surfaces for chronic neural interfaces. Nature Materials, 2012; DOI: 10.1038/nmat3468

Cite This Page:

University of Michigan. "Better brain implant: Slim electrode cozies up to single neurons." ScienceDaily. ScienceDaily, 11 November 2012. <www.sciencedaily.com/releases/2012/11/121111152932.htm>.
University of Michigan. (2012, November 11). Better brain implant: Slim electrode cozies up to single neurons. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2012/11/121111152932.htm
University of Michigan. "Better brain implant: Slim electrode cozies up to single neurons." ScienceDaily. www.sciencedaily.com/releases/2012/11/121111152932.htm (accessed July 29, 2014).

Share This




More Mind & Brain News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Losing Sleep Leaves You Vulnerable To 'False Memories'

Losing Sleep Leaves You Vulnerable To 'False Memories'

Newsy (July 27, 2014) A new study shows sleep deprivation can make it harder for people to remember specific details of an event. Video provided by Newsy
Powered by NewsLook.com
University Quiz Implies Atheists Are Smarter Than Christians

University Quiz Implies Atheists Are Smarter Than Christians

Newsy (July 25, 2014) An online quiz from a required course at Ohio State is making waves for suggesting atheists are inherently smarter than Christians. Video provided by Newsy
Powered by NewsLook.com
Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

AFP (July 24, 2014) A so-called drugs rehab 'clinic' is closed down in Pakistan after police find scores of ‘patients’ chained up alleging serial abuse. Duration 03:05 Video provided by AFP
Powered by NewsLook.com
New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins