Bulk-heterojunction photocapacitors with high open-circuit voltage for low light intensity photostimulation of neurons

High-level transduction control of light to bioelectricity is an important goal for the realization of superior neuron-device interfaces that can be used for regulating fundamental cellular processes to cure neurological disorders. In this study, a single-junction, wireless, and capacitive-charge-injecting optoelectronic biointerface with negligible faradaic reactions by using a high open-circuit voltage (0.75 V) bulk heterojunction of PTB7-Th:PC71BM is designed and demonstrated. The biointerface generates a 2-fold higher photocurrent in comparison with P3HT:PC61BM having an open-circuit voltage of 0.55 V. Furthermore, we observed that light intensity is logarithmically correlated with the open-circuit voltage of solar cells, and the photovoltage of the biointerfaces varies the switching speed of capacitive charge-transfer. Finally, pulse trains of capacitive stimuli at a low light intensity of 20 mW cm(-2) elicit action potential generation in primary hippocampal neurons extracted from E15-E17 Wistar Albino rats. These findings show the great promise of high open-circuit voltage bulk heterojunction biointerfaces for non-genetic, all-optical and safe modulation of neurons.

Automated summary

This study demonstrates a high-level transduction control of light to bioelectricity for superior neuron-device interfaces, using a high open-circuit voltage bulk heterojunction. The relationship between light intensity and voltage, as well as the impact of photovoltage on charge transfer speed, were investigated. Additionally, the potential of the biointerfaces with high open-circuit voltage for non-genetic, all-optical modulation of neurons was highlighted.