Motivation
Cortically implanted microelectrode arrays (MEAs) are essential for enabling brain-machine interfaces that restore sensory or motor function and facilitate exploration of complex neural networks. A critical bottleneck in MEA performance is the electrode material, which must balance low impedance, biostability, and biocompatibility. While materials like iridium oxide (SIROF) have shown success in long-term neural recordings, their high cost and scalability limit widespread adoption. Ruthenium oxide (RuOx), a lower-cost alternative, has shown similar electrochemical properties to SIROF in acute settings. However, its long-term stability and recording performance remain underexplored. This project aims to evaluate RuOx as a cost-effective and scalable electrode material by assessing its chronic recording and electrochemical stability in vivo, providing critical data to support its potential for future neural interface applications.
Our Solution
To address the need for cost-effective, stable, and scalable low-impedance coatings for neural recording electrodes, we evaluated sputtered ruthenium oxide (RuOx) as a viable alternative to the more expensive iridium-based coatings like SIROF. By applying 120 nm thick RuOx films to a-SiC microelectrode arrays and implanting them into rat motor cortex, we systematically assessed electrochemical stability (via impedance spectroscopy and cyclic voltammetry) and recording fidelity (via single-unit recordings) over a 6-week subchronic period. Our results demonstrate that RuOx maintains stable impedance, charge storage capacity, and consistent signal quality over time, with recording performance comparable to SIROF. This supports RuOx as a promising, low-cost, and scalable electrode material for chronic neural interfaces.
My Contributions
I contributed to both the experimental and analytical components of the RuOx electrode study and led the design of the research poster titled "Chronic Stability of Ruthenium Oxide Electrodes in Rat Motor Cortex." I assisted in collecting in vivo electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) data from implanted a-SiC MEAs and played a role in preprocessing and interpreting these datasets, focusing on impedance changes at key frequency bands and charge storage capacity across sweep rates. For the neural recording component, I supported spike sorting, unit identification, and quantification of key metrics including peak-to-peak voltage (Vpp), signal-to-noise ratio (SNR), and active electrode yield (AEY) across the 16-week timeline. My analysis helped confirm the electrochemical and recording stability of RuOx films over time. I independently developed the scientific poster, synthesizing experimental methods, data trends, and statistical results into a coherent visual narrative aimed at technical audiences, and presented the findings at UT Dallas’s Undergraduate Research Symposium.
Project Outcomes
Poster: URSA 25 Poster
These publications are based on the broader research project I supported (not listed as an author): Chronic Stability of Ruthenium Oxide Electrodes in Rat Motor Cortex
Looking to discuss further? Contact me at research@mkmaharana.com
