title: In vitro biocompatibility of various polymer-based microelectrode arrays for retinal prosthesis.
abstract: OBJECTIVE
  The purpose of our study is to evaluate the biocompatibility of various polymers used as microelectrode arrays (MEAs) in retinal prostheses through in vitro cytotoxicity testing following a standardized
  
  
  METHODS
  
  
  
  METHODS
  Three types of polymer-based MEAs were examined: silicone-based platinum, polyimide-based gold and liquid crystal polymer (LCP)-based gold MEAs. The silicone/platinum MEAs were fabricated by a Nd:YAG laser, polyimide/gold MEAs by a semiconductor manufacturing technique, and LCP/gold MEAs by laser micromachining and thermal-bonding process. All experimental procedures followed the International Organization for Standardization (ISO) 10993-5. To obtain the extracts of specimens, 4 g of each type of MEA were eluted by culture media, MEM, for 24 hours. Then, several diluents of extracts, including the original extracts, were applied to a cultured-cell monolayer, L929 fibroblasts. The morphologic changes of cells were analyzed by microscope after 24 and 48 hours of incubation. The quantitative evaluations of cell viability were performed by MTT assay after 24 hours of incubation.
  
  
  RESULTS
  The microscopic evaluations revealed that extracts from polymer-based MEAs did not induce morphologic changes or reduction of cells compared with control irrespective of concentrations of extracts. The MTT assay showed high viability values of approximately 80 to 130% regardless of diluted ratio of extracts from polymer-based MEAs. None of the polymers demonstrated a significant reduction of cell viability when compared with control.
  
  
  CONCLUSIONS
  All types of polymer-based MEAs, including silicone/platinum, polyimide/gold, and LCP/gold MEAs, meet the criteria of biocompatibility guided by international standards, ISO 10993-5.
authors.affiliation: Department of Ophthalmology, Kangnam Sacred Heart Hospital, College of Medicine, Hallym University, Seoul, Republic of Korea.
authors.forename: So Hyun
authors.initials: SH
authors.lastname: Bae
authors.forename: Jeong-Hwan
authors.initials: JH
authors.lastname: Che
authors.forename: Jong-Mo
authors.initials: JM
authors.lastname: Seo
authors.forename: Joonsoo
authors.initials: J
authors.lastname: Jeong
authors.forename: Eui Tae
authors.initials: ET
authors.lastname: Kim
authors.forename: Seung Woo
authors.initials: SW
authors.lastname: Lee
authors.forename: Kyo-in
authors.initials: KI
authors.lastname: Koo
authors.forename: Gregg J
authors.initials: GJ
authors.lastname: Suaning
authors.forename: Nigel H
authors.initials: NH
authors.lastname: Lovell
authors.forename: Dong-Il Dan
authors.initials: DI
authors.lastname: Cho
authors.forename: Sung June
authors.initials: SJ
authors.lastname: Kim
authors.forename: Hum
authors.initials: H
authors.lastname: Chung
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000633:toxicity*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004558:Electric Stimulation / Q000295:instrumentation*; D004567:Electrodes, Implanted; D005347:Fibroblasts / Q000187:drug effects*; D008422:Materials Testing; D051379:Mice; D008839:Microelectrodes; D008858:Microscopy, Phase-Contrast; D011108:Polymers / Q000633:toxicity*; D057488:Visual Prosthesis / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D011108:Polymers