Should you need any electrode implants for your neurons at some point in the future, it’s possible they could be coated with gold. Researchers at the Lawrence Livermore National Laboratory (LLNL) and at the University of California at Davis (UC Davis) have discovered that electrodes covered in nanoporous gold could prevent scarring (from a May 5, 2015 news item on Azonano),
A team of researchers from Lawrence Livermore and UC Davis have found that covering an implantable neural electrode with nanoporous gold could eliminate the risk of scar tissue forming over the electrode’s surface.
The team demonstrated that the nanostructure of nanoporous gold achieves close physical coupling of neurons by maintaining a high neuron-to-astrocyte surface coverage ratio. Close physical coupling between neurons and the electrode plays a crucial role in recording fidelity of neural electrical activity.
An April 30, 2015 LLNL news release, which originated the news item, details the scarring issue and offers more information about the proposed solution,
Neural interfaces (e.g., implantable electrodes or multiple-electrode arrays) have emerged as transformative tools to monitor and modify neural electrophysiology, both for fundamental studies of the nervous system, and to diagnose and treat neurological disorders. These interfaces require low electrical impedance to reduce background noise and close electrode-neuron coupling for enhanced recording fidelity.
Designing neural interfaces that maintain close physical coupling of neurons to an electrode surface remains a major challenge for both implantable and in vitro neural recording electrode arrays. An important obstacle in maintaining robust neuron-electrode coupling is the encapsulation of the electrode by scar tissue.
Typically, low-impedance nanostructured electrode coatings rely on chemical cues from pharmaceuticals or surface-immobilized peptides to suppress glial scar tissue formation over the electrode surface, which is an obstacle to reliable neuron−electrode coupling.
However, the team found that nanoporous gold, produced by an alloy corrosion process, is a promising candidate to reduce scar tissue formation on the electrode surface solely through topography by taking advantage of its tunable length scale.
“Our results show that nanoporous gold topography, not surface chemistry, reduces astrocyte surface coverage,” said Monika Biener, one of the LLNL authors of the paper.
Nanoporous gold has attracted significant interest for its use in electrochemical sensors, catalytic platforms, fundamental structure−property studies at the nanoscale and tunable drug release. It also features high effective surface area, tunable pore size, well-defined conjugate chemistry, high electrical conductivity and compatibility with traditional fabrication techniques.
“We found that nanoporous gold reduces scar coverage but also maintains high neuronal coverage in an in vitro neuron-glia co-culture model,” said Juergen Biener, the other LLNL author of the paper. “More broadly, the study demonstrates a novel surface for supporting neuronal cultures without the use of culture medium supplements to reduce scar overgrowth.”
Here’s a link to and a citation for the paper,
Nanoporous Gold as a Neural Interface Coating: Effects of Topography, Surface Chemistry, and Feature Size by Christopher A. R. Chapman, Hao Chen, Marianna Stamou, Juergen Biener, Monika M. Biener, Pamela J. Lein, and Erkin Seker. ACS Appl. Mater. Interfaces, 2015, 7 (13), pp 7093–7100 DOI: 10.1021/acsami.5b00410 Publication Date (Web): February 23, 2015
Copyright © 2015 American Chemical Society
This paper is behind a paywall.
The researchers have provided this image to illustrate their work,