Flexible and Biocompatible Photoacoustic Film for Vision Restoration at Ultrahigh Spatial Resolution

Retinal degenerative diseases represent a major factor leading to irreversible blindness. Despite extensive research efforts, a definitive curative treatment remains elusive. The development of retinal prostheses, encompassing bionic and photovoltaic devices, has aimed to address this unmet clinical need. However, these technologies face inherent issues such as crosstalk from current leakage impacting spatial resolution, limitations in electrode numbers limiting the visual angle, and difficulties related to internal strain during fabrication. To address these challenges, we introduce a novel solution utilizing a uniform and flexible photoacoustic film composed of candle soot and polydimethylsiloxane for high-precision retinal stimulation as a subretinal implant. This approach leverages on the advantages of light patterning flexibility to overcome the limitations of unit spacing, electrode numbers, and internal strain observed in other devices. Our experiments demonstrate that this photoacoustic film effectively stimulates the retinas of blind rats ex vivo, achieving a spatial resolution of 50 µm. Moreover, upon implantation in rats, this flexible photoacoustic film exhibits superior biocompatibility. Significantly, the photoacoustic stimulation induced visual responses that were recorded in the rat brain's visual cortex. These findings hold promise for the restoration of vision in individuals suffering from age-related macular degeneration and retinal dystrophy, offering a potential solution with improved spatial resolution and better biocompatibility.