P3HT:ITIC polymer based photovoltaic biointerfaces for neural photostimulation

Aims/Purpose: Optoelectronic neural interfaces have diverse applications in comprehending neural network and treatment of neurodegenerative conditions especially in the field of the vision impairments. We aimed to use the non‐invasive, capacitive photocurrent generation stimulated by near‐infrared light in the biological environment integrating P3HT:ITIC devices to provide neuroprotective and neurodegenerative effects with reducing axonal damage through local repetitive photo‐stimulation. Methods: In this study, we performed neuron stimulation with the help of ITO/ZnO/P3HT:ITIC photoactive polymer implant placed on an indium tin oxide (ITO) glass. To evaluate the biocompatibility of the P3HT:ITIC devices, CTG cell viability and LDH leak assay were performed on primary nervous and visual system cells including Mio‐M1 and primary astrocytes. Cell specific biomarkers were examined by immunofluorescence staining to demonstrate short‐ and long‐term morphological changes and neural network improvements on both the biointerface and ITO control substrates. Results: We fabricated NIR‐responsive photovoltaic P3HT:ITIC biointerface with ZnO nanoparticles (NPs) as electron transport layer and P3HT:ITIC thin films as photoactive layer on ITO glass substrates. After evaluation of their stability, we showed that primary neurons, astrocytes and Müller glia cells on the biointerface have high cell viability, low cytotoxicity and preserved cellular network and morphology after 2 weeks of culture condition. Conclusions: Our study will provide novel solutions to existing problems in electrostimulation devices by exploring capabilities of wirelessly functional, biocompatible organic polymer‐based photoelectric devices with low cost of production. They have a potential in establishing a platform for the development of near infrared light‐controlled electrostimulation treatment, that can improve axonal healing in retina and optic nerve injuries.