Maya-Vetencourt, J. F. | bioRxiv Science

bioRxiv2022

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 prosthesis was recently engineered consisting of a dual poly-3-hexylthiophene (P3HT) and graphene layer onto a flexible substrate. Here, this hybrid prosthesis was subretinally implanted in vivo in 5-month-old Royal College of Surgeons (RCS) rats, a rodent model of RP. Implanted dystrophic rats restored visual performances 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 suitably employed for the rescue of retinal dystrophies and supports the translation of the organic strategy into the medical practice. TABLE OF CONTENTSInspired by organic photovoltaic, a hybrid retinal prosthesis consisting of poly-3-hexylthiophene (P3HT) and graphene on a flexible substrate was subretinally implanted in vivo in Royal College of Surgeons (RCS) rats, a model of Retinitis pigmentosa. Implanted dystrophic rats restored visual performances at both subcortical and cortical levels in response to light stimuli, in the absence of marked inflammatory responses. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=37 SRC="FIGDIR/small/507903v1_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@1cb30a0org.highwire.dtl.DTLVardef@e57c2corg.highwire.dtl.DTLVardef@3b3c8corg.highwire.dtl.DTLVardef@10442d7_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2019

A Membrane-Targeted Photoswitch Potently Modulates Neuronal Firing

Optical technologies allowing modulation of neuronal activity at high spatio-temporal resolution are becoming paramount in neuroscience. We engineered novel light-sensitive molecules by adding polar groups to a hydrophobic backbone containing azobenzene and azepane moieties. We demonstrate that the probes stably partition into the plasma membrane, with affinity for lipid rafts, and cause thinning of the bilayer through their trans-dimerization in the dark. In neurons pulse-labeled with the compound, light induces a transient hyperpolarization followed by a delayed depolarization that triggers action potential firing. The fast hyperpolarization is attributable to a light-dependent decrease in capacitance due to membrane relaxation that follows disruption of the azobenzene dimers. The physiological effects are persistent and can be evoked in vivo after labeling the mouse somatosensory cortex. These data demonstrate the possibility to trigger neural activity in vitro and in vivo by modulating membrane capacitance, without directly affecting ion channels or local temperature.

neuroscience↗