Abstract
Presentation Description :
The degeneration of photoreceptors in the retina is one of the major causes of adult blindness in humans. Unfortunately, no effective clinical treatments exist for the majority of retinal degenerative disorders. We exploited organic electronics, in particular photovoltaic semiconducting polymers, for the generation of a fully organic retinal prosthesis, to restore light sensitivity in degenerate retinas. We found that primary neurons grown onto a semiconductor polymer (P3HT) coating a conductive indium-tin oxide layer are depolarized and fire action potentials by appropriate light stimuli with a spatial resolution in the order of the neuronal cell body. Light stimulation of degenerate retinas placed on the organic polymer in subretinal configuration showed that a light stimulus in the daylight range of intensity elicited intense spiking activity in retinal ganglion cells to levels indistinguishable from those recorded in control retinas. We now report on the fabrication and functional validation of a fully organic prosthesis made of P3HT as a photosensitive semiconductive layer, PEDOT:PSS as a conductive layer and silk fibroin as a biocompatible passive substrate for long-term in vivo subretinal implantation in the eye of Royal College of Surgeons rats, a widely recognized model of Retinitis pigmentosa. Electrophysiological and behavioral analyses revealed a prosthesis-dependent recovery of light sensitivity and visual acuity that persisted up to 6-10 months after surgery. The rescue of the visual function was accompanied by an increase in the basal metabolic activity of the primary visual cortex, as demonstrated by PET imaging. Our results highlight the possibility of developing a new generation of organic, highly biocompatible and functionally autonomous prostheses for subretinal implants to treat degenerative blindness.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.