Electrodeposited Biocompatible Coatings for 3D Electrodes on Retinal Prostheses
- 1University of Central Florida
Abstract
Photovoltaic subretinal prosthesis, PRIMA, provides central vision to patients blinded by age-related macular degeneration, with acuity matching the 100 m pixel size. Further miniaturization requires pillar electrodes to position the stimulating surfaces closer to the inner retinal neurons. While such structures can be electroplated in gold and coated on their tops with SIROF, the exposed gold sidewalls are not biocompatible. Sputtering or atomic layer deposition of protective coatings are unsuitable for selectively passivating the pillar structures without also coating the photosensitive regions and return electrodes of the implant. Here, we present a strategy for biocompatible coating of pillar sidewalls while preserving surrounding implant functionality. The approach combines non-critical photoresist lithography to protect planar return electrodes with electrodeposition of TiO2; or Pt onto gold pillar sidewalls. In-vivo studies demonstrated that both TiO2 and Pt coatings are biocompatible and prevent adverse reactions of the retinal tissue to gold. Since specific capacitance of electroplated TiO2 (25 F/cm2) is much lower than that of Pt (240 F/cm2), the former better limits the current from the side walls and ensures that charge injection occurs predominantly through the pillar tops coated with SIROF (~6 mF/cm2). Electrodeposition, combined with noncritical photolithography provides a scalable wafer-level solution for fabrication of biocompatible three-dimensional electro-neural interfaces, addressing a critical bottleneck in bioelectronics.
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BibTeX
@misc{shautsova2026electrodeposited,
title = {{Electrodeposited Biocompatible Coatings for 3D Electrodes on Retinal Prostheses}},
author = {V. Shautsova and E. Butt and M. B. Bhuckory and L. M. Vu and D. Pham-Howard and V. Mamchik and L. Galambos and J. An and A. Shin and K. Mathieson and T. Kamins and D. Palanker},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.06.749620},
url = {https://www.biorxiv.org/content/10.64898/2026.09.06.749620v1},
note = {CC BY-ND},
}
RIS
TY - UNPB
TI - Electrodeposited Biocompatible Coatings for 3D Electrodes on Retinal Prostheses
AU - V. Shautsova
AU - E. Butt
AU - M. B. Bhuckory
AU - L. M. Vu
AU - D. Pham-Howard
AU - V. Mamchik
AU - L. Galambos
AU - J. An
AU - A. Shin
AU - K. Mathieson
AU - T. Kamins
AU - D. Palanker
PY - 2026
DA - 2026/09/06
PB - bioRxiv
DO - 10.64898/2026.09.06.749620
UR - https://www.biorxiv.org/content/10.64898/2026.09.06.749620v1
AB - Photovoltaic subretinal prosthesis, PRIMA, provides central vision to patients blinded by age-related macular degeneration, with acuity matching the 100 m pixel size. Further miniaturization requires pillar electrodes to position the stimulating surfaces closer to the inner retinal neurons. While such structures can be electroplated in gold and coated on their tops with SIROF, the exposed gold sidewalls are not biocompatible. Sputtering or atomic layer deposition of protective coatings are unsuitable for selectively passivating the pillar structures without also coating the photosensitive regions and return electrodes of the implant. Here, we present a strategy for biocompatible coating of pillar sidewalls while preserving surrounding implant functionality. The approach combines non-critical photoresist lithography to protect planar return electrodes with electrodeposition of TiO2; or Pt onto gold pillar sidewalls. In-vivo studies demonstrated that both TiO2 and Pt coatings are biocompatible and prevent adverse reactions of the retinal tissue to gold. Since specific capacitance of electroplated TiO2 (25 F/cm2) is much lower than that of Pt (240 F/cm2), the former better limits the current from the side walls and ensures that charge injection occurs predominantly through the pillar tops coated with SIROF (~6 mF/cm2). Electrodeposition, combined with noncritical photolithography provides a scalable wafer-level solution for fabrication of biocompatible three-dimensional electro-neural interfaces, addressing a critical bottleneck in bioelectronics.
ER -