P3ht-Graphene Device for the Restoration of Visual Properties in a Rat Model of Retinitis Pigmentosa

Retinal degeneration is one of the prevalent causes of blindness worldwide, for which no effective treatment has yet been identified. Inorganic photovoltaic devices have been investigated for visual restoration in advanced stage Retinitis pigmentosa (RP), although lack of implant flexibility and foreign-object reactions have limited their application. Organic photoactive retinal prostheses may overcome these limitations, being biomimetic and tissue friendly. Inspired by organic photovoltaic strategies involving graphene, a hybrid retinal pros- thesis is recently engineered consisting of a dual poly-3-hexylthiophene (P3HT) and graphene layer onto a flexible substrate. Here, this hybrid prosthesis is subretinally implanted in vivo in 5-month-old Royal College of Surgeons (RCS) rats, a rodent model of RP. Implanted dystrophic rats restored visual perfor- mances at both subcortical and cortical levels in response to light stimuli, in the absence of marked inflammatory responses. Moreover, the analysis of the physical-mechanical properties after prolonged permanence in the eye showed excellent biocompatibility and robustness of the device. Overall, the results demonstrate that graphene-enhanced organic photovoltaic devices can be suit- ably employed for the rescue of retinal dystrophies and supports the transla- tion of the organic strategy into medical practice.