title: A silicone fiber coating as approach for the reduction of fibroblast growth on implant electrodes.
abstract: In cochlear implant (CI) patients, an increase in electrode impedance due to fibrotic encapsulation is frequently observed. Several attempts have been proposed to reduce fibroblast growth at the electrode contacts, but none proved to be satisfactory so far. Here, a silicone fiber coating of the electrode contacts is presented that provides a complex micro-scale surface topography and increases hydrophobicity to inhibit fibroblast growth and adhesion. A silicone fiber electrospinning process was developed to create a thin and porous fiber mesh. Fiber coatings were applied on graphite specimen holders, glass cover slips and CI electrode contacts. For characterization of the coating's pore distribution, water contact angle and electrical impedance were analyzed. Cytotoxicity and in vitro fibroblast growth were evaluated to assess biological efficacy of the coatings. It could be shown that the silicone fiber mesh itself had only minor influence on electrode impedance. A uniform, hydrophobic fiber coating could be achieved that decreased fibroblast growth without showing toxic effects. Finally, CI electrode contacts were successfully coated in order to present this promising approach for a long-term improvement of CI electrodes. We are one of the first groups that could successfully adapt the electrospinning technique on the utilization of silicone. Silicone was chosen because of its high hydrophobicity, chemical stability and excellent biocompatibility and as it is one of the biomaterials already used in CIs. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2574-2580, 2017.
authors.affiliation: Department of Material Science, Faculty II, University of Applied Sciences and Arts Hannover, Germany.|Institute of Micro Production Technology, Leibniz Universität Hannover, Germany.
authors.forename: Folke
authors.initials: F
authors.lastname: Dencker
authors.affiliation: Institute for Multiphase Processes, Leibniz Universität Hannover, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Dreyer
authors.affiliation: Department of Material Science, Faculty II, University of Applied Sciences and Arts Hannover, Germany.
authors.forename: Dietrich
authors.initials: D
authors.lastname: Müller
authors.affiliation: Institute for Multiphase Processes, Leibniz Universität Hannover, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Zernetsch
authors.affiliation: Department of Otolaryngology, Hannover Medical School, Germany.|Cluster of Excellence "Hearing4all", Hannover Medical School, Germany.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Paasche
authors.affiliation: Department of Material Science, Faculty II, University of Applied Sciences and Arts Hannover, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Sindelar
authors.affiliation: Institute for Multiphase Processes, Leibniz Universität Hannover, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Glasmacher
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003054:Cochlear Implants; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D051379:Mice; D041681:NIH 3T3 Cells; D012828:Silicones / Q000737:chemistry*
chemical_list: D020099:Coated Materials, Biocompatible; D012828:Silicones
keywords: cochlear implant; electrospinning; silicone fiber