Article
Development of a flexible 60-channel PFA film-based electrode for high-resolution retinal stimulation
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Authors
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Jisung Kim
- Department of Transdisciplinary Medicine, Seoul National University of Hospital, South Korea
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J.S. Lee
- Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, South Korea
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C.H. Baek
- Department of Transdisciplinary Medicine, Seoul National University of Hospital, South Korea
| Published: | May 9, 2025 |
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Outline
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Objective: To develop and describe a flexible, high-resolution 60-channel electrode, based on PFA fluoropolymer film multilayer electrode is designed to enhance the resolution of retinal prostheses by increasing the number of stimulation sites compared to the previously developed 20-channel electrode.
Materials and Methods: The 60-channel electrode was fabricated using PFA, a thermoplastic fluoropolymer. The electrode consists of three layers of PFA film, thermally laminated using a Teflon-coated aluminum jig to align the layers. The total thickness of the structure is around 100 µm, making it suitable for subretinal prosthesis. To increase the charge injection limit, a 5 µm layer of porous gold was electroplated onto the stimulation sites,
Results: The flexible PFA-based electrode achieved a high-resolution structure with enhanced electrochemical properties suitable for subretinal stimulation. The thermal lamination process ensured a robust and flexible design, and the addition of porous gold significantly increased the charge storage capacity (CSC) by 0.2285 C/cm². Impedance was measured at 1 kHz, yielding a value of 1.1 kΩ.
Discussion: The 60-channel PFA-based electrode presents a path toward fully monolithic encapsulation of retinal prosthesis systems using PFA’s thermoplastic properties. By eliminating the need for feedthroughs, this approach simplifies fabrication, enhances reliability, and improves device longevity. Monolithic encapsulation would enable seamless integration of components, offering better biocompatibility, flexibility, and performance for subretinal applications.
Acknowledgment: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) 1711201073.
