Liquid-metal-based three-dimensional microelectrode arrays integrated with implantable ultrathin retinal prosthesis for vision restoration

Electronic retinal prostheses show promise for vision restoration, but conventional implants' rigidity can damage the retina and limit selectivity. This study presents a 10 µm-thick soft artificial retina integrating flexible, ultrathin photosensitive transistors with 3D eutectic gallium-indium (EGaIn) alloy electrodes. Platinum nanoclusters on the electrode tips reduce impedance, enhancing proximity to retinal ganglion cells (RGCs) and effective charge injection. The low Young's modulus of EGaIn minimizes retinal damage. An unsupervised machine learning approach identifies evoked spikes to grade neural activity. *In vivo* experiments in a retinal degeneration mouse model show that the spatiotemporal distribution of neural responses maps under selective localized illumination, suggesting vision restoration.

Won Gi Chung, Jiuk Jang, Gang Cui, Sanghoon Lee, Han Jeong, Haisu Kang, Hunkyu Seo, Sumin Kim, Enji Kim, Junwon Lee, Seung Geol Lee, Suk Ho Byeon, Jang-Ung Park