Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Electrode shape improves neurostimulation for small targets

25.04.2018

A cross-like shape helps the electrodes of implantable neurostimulation devices to deliver more charge to specific areas of the nervous system, possibly prolonging device life span, says research published in March in Scientific Reports.

The shape, called "fractal," would be particularly useful for stimulating smaller areas, such as deep brain structures or the retina, since it maximizes perimeter within a smaller surface area - providing the higher resolution needed for restoring bodily functions and potentially enabling neurostimulation devices to last longer in the body without a recharge.


This small chip holds a 2-D electrode with a shape that can better stimulate small targets in the body over time.

Credit: Purdue University image/Kayla Wiles

"There are challenges with shrinking the size of these electrodes," said Hyowon "Hugh" Lee, assistant professor of biomedical engineering. "If you shrink them too small, then you can't inject enough energy to be able to activate the underlying substrate."

Industry currently produces circular or rectangular electrodes for neurostimulation devices. "There's really no reason to maintain these shapes other than the fact that it makes it easier for the conventional manufacturing techniques to facilitate," Lee said.

"But microfabrication allows batch processing or even more scalable roll-to-roll fabrication, in which we have the design freedom to create any type of electrode design with high resolution to improve their functionality."

Lee's lab experimented with other shapes that could better inject charge with electrode size limitations. The fractal shape outperformed conventional shapes and the "serpentine," or snake-like shape, even though it has a similar perimeter to surface area ratio as fractal. This could be because the repeating patterns of the fractal design better facilitate the continuous diffusion of charge transfer species, or reactants, to the platinum electrode surface.

"When you have a lot more diffusion of species to the surface, it allows for faster Faradaic charge transfer from the electrode surface," Lee said. The charge then reaches a threshold on neurons to trigger an action potential, or electrochemical signal, to stimulate a target.

Because fractal designs also feature lower impedance than conventional electrodes, they could allow more charge to be injected onto an electrode surface over time and extend the life span of neurostimulation devices. "If you have less load, meaning it takes less energy to get the same effect, then the fixed battery life of implantable stimulation devices is going to be improved," Lee said.

The next step is to test the robustness and longevity of fractal designed-electrodes in comparison to conventional shapes. Lee's lab is also looking into using the fractal design for improving sensitivity in devices such as biosensors. "The goal would be better control of stimulation over targeted areas and more pinpointed therapy," Lee said.

###

ABSTRACT

Electrochemical evaluations of fractal microelectrodes for energy efficient neurostimulation
Hyunsu Park1, Pavel Takmakov2, Hyowon Lee1
1Purdue University, West Lafayette, IN, USA
2White Oak Federal Research Center, Silver Spring, MD, USA
doi: 10.1038/s41598-018-22545-w

Advancements in microfabrication has enabled manufacturing of microscopic neurostimulation electrodes with smaller footprint than ever possible. The smaller electrodes can potentially reduce tissue damage and allow better spatial resolution for neural stimulation. Although electrodes of any shape can easily be fabricated, substantial effort have been focused on identification and characterization of new materials and surface morphology for efficient charge injection, while maintaining simple circular or rectangular Euclidean electrode geometries. In this work we provide a systematic electrochemical evaluation of charge injection capacities of serpentine and fractal-shaped platinum microelectrodes and compare their performance with traditional circular microelectrodes. Our findings indicate that the increase in electrode perimeter leads to an increase in maximum charge injection capacity. Furthermore, we found that the electrode geometry can have even more significant impact on electrode performance than having a larger perimeter for a given surface area. The fractal shaped microelectrodes, despite having smaller perimeter than other designs, demonstrated superior charge injection capacity. Our results suggest that electrode design can significantly affect both Faradaic and non-Faradaic electrochemical processes, which may be optimized to enable a more energy efficient design for neurostimulation.

Media Contact

Kayla Wiles
wiles5@purdue.edu
765-494-2432

 @PurdueUnivNews

http://www.purdue.edu/ 

Kayla Wiles | EurekAlert!
Further information:
http://www.purdue.edu/newsroom/releases/2018/Q2/electrode-shape-improves-neurostimulation-for-small-targets.html
http://dx.doi.org/10.1038/s41598-018-22545-w

More articles from Medical Engineering:

nachricht Surgery involving ultrasound energy found to treat high blood pressure
24.05.2018 | Queen Mary University of London

nachricht XXL computed tomography: a new dimension in X-ray analysis
17.05.2018 | Fraunhofer-Gesellschaft

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>