title: A hydrogel coating for cochlear implant arrays with encapsulated adipose-derived stem cells allows brain-derived neurotrophic factor delivery.
abstract: CONCLUSIONS
  Human adipose-derived stem cells (ASCs), encapsulated in a fibrin-collagen hydrogel for the coating of an electrode array, produce sufficient amounts of neurotrophic factors and may be suitable for enhancing the bioelectric interface of cochlear implants (CIs).
  
  
  OBJECTIVE
  To evaluate different hydrogel compositions loaded with ASCs with regard to delivery of neuroactive substances and mechanical suitability for the coating of a CI electrode array.
  
  
  METHODS
  ASCs were cultivated in hydrogels consisting of collagen and fibrin in varying fractions (0:1, 1:1, 1:2, and 1:0). The cell proliferation and viability, as well as the production of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), and laminin were determined. Two hydrogel compositions were used as a coating for CI electrode arrays and tested in a scala tympani model.
  
  
  RESULTS
  Cell proliferation was best in collagen/fibrin hydrogel compositions (1:1 and 1:2) and increasing amounts of BDNF (up to 2.59 ng/ml) and laminin (up to 320 ng/ml) were detected. GDNF production was inconsistent and markedly lower. A sufficient coating of a CI electrode carrier in terms of stability and flexibility was achieved only with mixed compositions, although hydrogels formed bulky and uneven layers on the silicone surfaces.
authors.affiliation: Comprehensive Hearing Center, Department of Oto-Rhino-Laryngology, Plastic, Aesthetic and Reconstructive Head and Neck Surgery, University of Wuerzburg , Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Schendzielorz
authors.forename: Agmal
authors.initials: A
authors.lastname: Scherzed
authors.forename: Kristen
authors.initials: K
authors.lastname: Rak
authors.forename: Johannes
authors.initials: J
authors.lastname: Völker
authors.forename: Rudolf
authors.initials: R
authors.lastname: Hagen
authors.forename: Robert
authors.initials: R
authors.lastname: Mlynski
authors.forename: Katrin
authors.initials: K
authors.lastname: Frölich
authors.forename: Andreas
authors.initials: A
authors.lastname: Radeloff
mesh_terms: D053687:Adult Stem Cells / Q000166:cytology / Q000187:drug effects*; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D002478:Cells, Cultured; D019929:Cochlear Implantation; D003054:Cochlear Implants; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000378:metabolism; D006801:Humans; D020100:Hydrogels / Q000494:pharmacology*; D007797:Laminin / Q000378:metabolism
chemical_list: D019208:Brain-Derived Neurotrophic Factor; C495039:GDNF protein, human; D051100:Glial Cell Line-Derived Neurotrophic Factor; D020100:Hydrogels; D007797:Laminin; C579455:BDNF protein, human