June 2013
Volume 54, Issue 15
Free
ARVO Annual Meeting Abstract  |   June 2013
A polymer-based interface restores light sensitivity in rat blind retinas
Author Affiliations & Notes
  • Maurizio Mete
    Ophthalmology, Ospedale Sacro Cuore, Verona, Italy
  • Grazia Pertile
    Ophthalmology, Ospedale Sacro Cuore, Verona, Italy
  • Diego Ghezzi
    Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
  • Maria Rosa Antognazza
    Center for Nanoscience and Technology, Istituto Italiano di Tecnologia @POLIMI, Milano, Italy
  • Rita Maccarone
    Department of Biomedical Technology, University of L'Aquila, L'Aquila, Italy
  • Erica Lanzarini
    Center for Nanoscience and Technology, Istituto Italiano di Tecnologia @POLIMI, Milano, Italy
  • Nicola Martino
    Center for Nanoscience and Technology, Istituto Italiano di Tecnologia @POLIMI, Milano, Italy
  • Silvia Bisti
    Department of Biomedical Technology, University of L'Aquila, L'Aquila, Italy
  • Guglielmo Lanzani
    Center for Nanoscience and Technology, Istituto Italiano di Tecnologia @POLIMI, Milano, Italy
  • Fabio Benfenati
    Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
  • Footnotes
    Commercial Relationships Maurizio Mete, None; Grazia Pertile, None; Diego Ghezzi, None; Maria Rosa Antognazza, None; Rita Maccarone, None; Erica Lanzarini, None; Nicola Martino, None; Silvia Bisti, None; Guglielmo Lanzani, None; Fabio Benfenati, None
  • Footnotes
    Support None
Investigative Ophthalmology & Visual Science June 2013, Vol.54, 1403. doi:
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      Maurizio Mete, Grazia Pertile, Diego Ghezzi, Maria Rosa Antognazza, Rita Maccarone, Erica Lanzarini, Nicola Martino, Silvia Bisti, Guglielmo Lanzani, Fabio Benfenati; A polymer-based interface restores light sensitivity in rat blind retinas. Invest. Ophthalmol. Vis. Sci. 2013;54(15):1403.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: Sight restoration is one of the new frontiers for prosthetic devices that enable the electrical stimulation of neurons. In particular, diseases that affect the retinal pigment epithelium and photoreceptors but preserve the inner retinal layers are preferential targets for implantation of visual prostheses. We recently discovered that primary neurons can be successfully grown onto a transparent photovoltaic organic polymer and electrically stimulated by light. This result encouraged us to test the efficacy of this method in retinas explanted from albino rats with reproducibly induced photoreceptor degeneration due to light damage.

Methods: We investigated the ability of the polymer layer to restore light sensitivity in retinas explanted from albino rats with a light-induced degeneration of the photoreceptor layer. Acutely dissected retinas were placed on the organic polymer in a sub-retinal configuration (i.e., external layers in contact with the polymer). Light stimulation of the degenerate retina was observed by monitoring multi-unit activity and field potentials with an extracellular electrode positioned in the retinal ganglion cell layer.

Results: Multi-unit activity recordings showed that a light stimulus 16-fold lower than the safe limit for pulsed illumination elicited intense spiking activity in degenerate retinas placed on polymer-coated substrates to levels indistinguishable from those recorded in control retinas. Moreover, to evaluate the efficiency of the interface, a dose-response analysis of spiking activity versus light intensity were performed in degenerate retinas. Spiking activity was observed in degenerate retinas over the polymer with a response threshold below 0.3 μW/mm2, a linear increase in a range corresponding to daylight irradiance, and a response saturation above 100 μW/mm2 (considered the safe limit for chronic illumination). A 4-fold increase in the amplitude of the light response at saturation and a significant left shift of the dose-response curves were obtained in retinas placed over the polymer-coated interface respect to degenerate retinas on glass substrates.

Conclusions: Our finding indicate that the interface fully mimicks functional photoreceptors in activating the processing of the inner retina and is able to rescue normal light sensitivity. These results broaden the possibility of developing a new generation of fully organic prosthetic devices for sub-retinal implants.

Keywords: 607 nanotechnology • 508 electrophysiology: non-clinical • 494 degenerations/dystrophies  
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