title: Synthetic 3D diamond-based electrodes for flexible retinal neuroprostheses: Model, production and in vivo biocompatibility.
abstract: Two retinal implants have recently received the CE mark and one has obtained FDA approval for the restoration of useful vision in blind patients. Since the spatial resolution of current vision prostheses is not sufficient for most patients to detect faces or perform activities of daily living, more electrodes with less crosstalk are needed to transfer complex images to the retina. In this study, we modelled planar and three-dimensional (3D) implants with a distant ground or a ground grid, to demonstrate greater spatial resolution with 3D structures. Using such flexible 3D implant prototypes, we showed that the degenerated retina could mould itself to the inside of the wells, thereby isolating bipolar neurons for specific, independent stimulation. To investigate the in vivo biocompatibility of diamond as an electrode or an isolating material, we developed a procedure for depositing diamond onto flexible 3D retinal implants. Taking polyimide 3D implants as a reference, we compared the number of neurones integrating the 3D diamond structures and their ratio to the numbers of all cells, including glial cells. Bipolar neurones were increased whereas there was no increase even a decrease in the total cell number. SEM examinations of implants confirmed the stability of the diamond after its implantation in vivo. This study further demonstrates the potential of 3D designs for increasing the resolution of retinal implants and validates the safety of diamond materials for retinal implants and neuroprostheses in general.
authors.affiliation: INSERM, U968, Institut de la Vision, Paris F-75012, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S968, Institut de la Vision, Paris F-75012, France; CNRS UMR 7210, Institut de la Vision, Paris 75012, France.
authors.forename: Amel
authors.initials: A
authors.lastname: Bendali
authors.affiliation: ESIEE - ESYCOM Université Paris Est, Cité Descartes, BP99, 93162 Noisy Le Grand, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Rousseau
authors.affiliation: ESIEE - ESYCOM Université Paris Est, Cité Descartes, BP99, 93162 Noisy Le Grand, France.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Lissorgues
authors.affiliation: CEA-LIST, Diamond Sensors Laboratory, Gif-sur-Yvette, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Scorsone
authors.affiliation: INSERM, U968, Institut de la Vision, Paris F-75012, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S968, Institut de la Vision, Paris F-75012, France; CNRS UMR 7210, Institut de la Vision, Paris 75012, France.
authors.forename: Milan
authors.initials: M
authors.lastname: Djilas
authors.affiliation: INSERM, U968, Institut de la Vision, Paris F-75012, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S968, Institut de la Vision, Paris F-75012, France; CNRS UMR 7210, Institut de la Vision, Paris 75012, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Dégardin
authors.affiliation: INSERM, U968, Institut de la Vision, Paris F-75012, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S968, Institut de la Vision, Paris F-75012, France; CNRS UMR 7210, Institut de la Vision, Paris 75012, France.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Dubus
authors.affiliation: INSERM, U968, Institut de la Vision, Paris F-75012, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S968, Institut de la Vision, Paris F-75012, France; CNRS UMR 7210, Institut de la Vision, Paris 75012, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Fouquet
authors.affiliation: INSERM, U968, Institut de la Vision, Paris F-75012, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S968, Institut de la Vision, Paris F-75012, France; CNRS UMR 7210, Institut de la Vision, Paris 75012, France.
authors.forename: Ryad
authors.initials: R
authors.lastname: Benosman
authors.affiliation: CEA-LIST, Diamond Sensors Laboratory, Gif-sur-Yvette, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Bergonzo
authors.affiliation: INSERM, U968, Institut de la Vision, Paris F-75012, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S968, Institut de la Vision, Paris F-75012, France; CNRS UMR 7210, Institut de la Vision, Paris 75012, France; Fondation Ophtalmologique Adolphe de Rothschild, Paris, France; CHNO des Quinze-Vingts, Paris, France; Academie des Sciences, Paris, France.
authors.forename: José-Alain
authors.initials: JA
authors.lastname: Sahel
authors.affiliation: INSERM, U968, Institut de la Vision, Paris F-75012, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S968, Institut de la Vision, Paris F-75012, France; CNRS UMR 7210, Institut de la Vision, Paris 75012, France. Electronic address: serge.picaud@inserm.fr.
authors.forename: Serge
authors.initials: S
authors.lastname: Picaud
mesh_terms: D000818:Animals; D018130:Diamond / Q000737:chemistry*; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D005654:Fundus Oculi; D007091:Image Processing, Computer-Assisted; D008422:Materials Testing / Q000379:methods*; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D018583:Pliability; D011474:Prosthesis Design; D051381:Rats; D012160:Retina / Q000502:physiology*; D051245:Retinal Bipolar Cells / Q000166:cytology; D057488:Visual Prosthesis
chemical_list: D018130:Diamond
keywords: 3D electrode; Bipolar cell; Diamond; Gliosis; Resolution; Retinal prostheses