# Neural Electrodes with Enhanced Charge Injection and Reduced Interfacial Impedance Using Graphenated Carbon Nanotubes Coated With Atomic Layer-Deposited Platinum Nanoparticles

> **NIH NIH R21** · DUKE UNIVERSITY · 2020 · $461,770

## Abstract

The objective of this project is to evaluate graphenated carbon nanotubes (gCNTs) as lower impedance,
smaller electrodes for neurostimulation, using deep brain stimulation (DBS) as a test case, with the long-term
goal of developing a new type of neural electrode with lower impedance and smaller size. Lower impedance of
the electrode-tissue interface results in lower power consumption, as a smaller voltage is required to achieve
the same charge injection. Lower power consumption extends battery life and decreases the size of the
batteries and thus of the implanted device. The minimum size of stimulating electrodes is limited by the
minimum charge injection required for effective stimulation. As well, the size of the electrode is an important
factor in the insertion damage created by electrode insertion and the specificity of the volume that can be
stimulated. Lower impendence, smaller electrodes will lead to less damaging electrodes and a combination of
smaller and longer lasting batteries. We will compare the performance of gCNT electrodes to standard
platinum electrodes using quantitative in vitro and in vivo measurements. We expect to increase the reversible
charge injection capacity by 20x and reduce the impedance by 65% versus the same-sized Pt electrode. The
specific aims of this project are: (1) Quantify the effect of gCNT morphology on charge injection, interfacial
impedance, and adhesion and identify processing conditions that improve these properties. (2) Deposit
platinum nanoparticles via atomic layer deposition (ALD) on gCNTs to further increase the charge injection
capacity and decrease impedance. These Pt-gCNTs will be deposited in a checkerboard pattern (balance Pt
electrodes) on a multielectrode array (MEA), allowing performance to be compared within animal (3). Test the
MEAs in vivo in hemiparkinsonian 6-OHDa lesioned rats, implanting electrodes into the subthalamic nucleus
and delivering chronic daily symptom-relieving DBS in order to assess Pt-gCNT vs Pt electrode performance.
In the applicant’s opinion, proposed research is innovative because it introduces a new material (gCNTs) and a
new process (ALD) that will improve the performance of neural electrodes. gCNTs are expected to have
significantly better performance than standard Pt electrodes. ALD has the capability to deposit nanoparticles in
a unique way that maximizes the amount of gCNTs surface area that is coated as well as the electrochemical
surface area of the platinum. Nanostructured platinum will be used to further enhance gCNTs’ neural electrode
performance. The outcome of this project will be a comprehensive assessment of Pt-gCNTs as highly efficient
neural stimulation electrodes. If realized, it will lead to neural stimulation electrodes that are smaller, limiting
insertion damage, and consume less power, thereby reducing the size and increasing the lifetime of batteries
and may expand the frontier of possible electrode systems.

## Key facts

- **NIH application ID:** 9924896
- **Project number:** 1R21EY031271-01
- **Recipient organization:** DUKE UNIVERSITY
- **Principal Investigator:** Charles Bernard Parker
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $461,770
- **Award type:** 1
- **Project period:** 2020-09-01 → 2024-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9924896

## Citation

> US National Institutes of Health, RePORTER application 9924896, Neural Electrodes with Enhanced Charge Injection and Reduced Interfacial Impedance Using Graphenated Carbon Nanotubes Coated With Atomic Layer-Deposited Platinum Nanoparticles (1R21EY031271-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9924896. Licensed CC0.

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