Kriti Panchal¹, Wesley Seche², Henna Khosla³, Gang Feng³, Jacob Elmer³, Steven J. May¹, Ekaterina Pomerantseva¹, Shahram Amini^2,4
1Drexel University, Philadelphia, PA
²Pulse Technologies Inc. (An Integer Holdings Company), Quakertown, PA
³Villanova University, Villanova, PA
⁴University of Connecticut, Storrs, CT
Hierarchically restructured (HSR) electrodes have gained significant attention for implantable device applications due to their large effective surface area, high charge storage capability, and improved electrochemical stability. However, most high-performance HSR electrodes rely on noble metals such as platinum, iridium or silver. While these materials are biocompatible and electrochemically reliable, they are expensive and limited in availability. Even small reductions in material expenses can significantly influence overall production costs when manufacturing implantable devices at large scale. Lower-priced electrode materials can therefore improve the economic feasibility of device fabrication, making implantable technologies more affordable and accessible within the healthcare system.
Titanium is a well-established biocompatible material for implantable applications. Compared to noble metals (such as platinum, iridium, silver), titanium is orders of magnitude less expensive and has been widely used in biomedical implants, including various orthopedic and dental applications. Its proven biocompatibility and corrosion resistance make titanium a suitable and reliable material for implantable electrode development. In our previous work, flat Ti substrates were laser restructured under a nitrogen atmosphere to limit excessive oxidation of the bulk electrode, as TiO₂ is electrically insulating. The resulting Ti HSR electrodes exhibited a capacitance of approximately ~400 μF·mm^-2 in cyclic voltammetry (CV) experiments, which is comparable to that of previously reported HSR Pt10Ir electrodes. In addition, the Ti HSR electrodes maintained stable electrochemical performance over extended CV cycling, demonstrating good structural and electrochemical stability.
Building on the favorable electrochemical performance of Ti HSR electrodes, this work advances the platform by incorporating antibacterial functionality as a strategy to reduce the risk of surgical site and post-implantation infections. Such infections remain among the most serious complications associated with implantable devices. Moreover, the widespread use of antibiotics has contributed to the growing challenge of antibiotic resistance. Integrating antibacterial activity directly into implantable electrodes offers a promising route to address these challenges while reducing reliance on systemic antibiotic treatments. In this study, to achieve antibacterial functionality, Ti HSR electrodes were sputter-deposited with a well-established antibacterial material, copper oxide (CuO). The effect of ~30 nm thick CuO coating on electrochemical performance was investigated through CV cycling, and CuO-coated Ti HSR electrodes showed increased capacitance of ~500 μF·mm-2, attributed to good electrical conductivity and pseudocapacitive redox activity of CuO. Zone of inhibition studies are in progress to evaluate the antibacterial activity of the CuO-coated Ti HSR electrodes, and the results will be discussed in the presentation.
Overall, this work demonstrates a scalable and multifunctional Ti-based HSR electrode platform for implantable device applications.