title: The use of a dual PEDOT and RGD-functionalized alginate hydrogel coating to provide sustained drug delivery and improved cochlear implant function.
abstract: Cochlear implants provide hearing by electrically stimulating the auditory nerve. Implant function can be hindered by device design variables, including electrode size and electrode-to-nerve distance, and cochlear environment variables, including the degeneration of the auditory nerve following hair cell loss. We have developed a dual-component cochlear implant coating to improve both the electrical function of the implant and the biological stability of the inner ear, thereby facilitating the long-term perception of sound through a cochlear implant. This coating is a combination of an arginine-glycine-aspartic acid (RGD)-functionalized alginate hydrogel and the conducting polymer poly(3, 4-ethylenedioxythiophene) (PEDOT). Both in vitro and in vivo assays on the effects of these electrode coatings demonstrated improvements in device performance. We found that the coating reduced electrode impedance, improved charge delivery, and locally released significant levels of a trophic factor into cochlear fluids. This coating is non-cytotoxic, clinically relevant, and has the potential to significantly improve the cochlear implant user's experience.
authors.affiliation: Neuroscience Program, University of Michigan, 4137 Undergraduate Research Bldg, 204 Washtenaw Ave., Ann Arbor, MI 48109-2215, USA. jchikar@umich.edu
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Chikar
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Hendricks
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Richardson-Burns
authors.forename: Yehoash
authors.initials: Y
authors.lastname: Raphael
authors.forename: Bryan E
authors.initials: BE
authors.lastname: Pfingst
authors.forename: David C
authors.initials: DC
authors.lastname: Martin
mesh_terms: D000464:Alginates / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000737:chemistry / Q000378:metabolism; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry* / Q000378:metabolism; D020099:Coated Materials, Biocompatible / Q000737:chemistry / Q000378:metabolism; D019929:Cochlear Implantation; D003054:Cochlear Implants; D003056:Cochlear Nerve / Q000502:physiology / Q000601:surgery; D003638:Deafness / Q000534:rehabilitation / Q000601:surgery; D016503:Drug Delivery Systems; D004563:Electrochemistry; D004566:Electrodes; D020723:Glucuronic Acid / Q000737:chemistry / Q000378:metabolism; D006168:Guinea Pigs; D006603:Hexuronic Acids / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D020100:Hydrogels / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D008422:Materials Testing; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism; D013499:Surface Properties
chemical_list: D000464:Alginates; D019208:Brain-Derived Neurotrophic Factor; D019086:Bridged Bicyclo Compounds, Heterocyclic; D020099:Coated Materials, Biocompatible; D006603:Hexuronic Acids; D020100:Hydrogels; D009842:Oligopeptides; D011108:Polymers; C121383:poly(3,4-ethylene dioxythiophene); C047981:arginyl-glycyl-aspartic acid; D020723:Glucuronic Acid