Volume 102, Issue 2 pp. 442-454
Original Article

Dexamethasone released from cochlear implant coatings combined with a protein repellent hydrogel layer inhibits fibroblast proliferation

Antonina Wrzeszcz

Corresponding Author

Antonina Wrzeszcz

Department of Otolaryngology, Hannover Medical School, 30625 Hannover, Germany

These authors contributed equally to this work.

Correspondence to: A. Wrzeszcz; e-mail: [email protected]Search for more papers by this author
Barbara Dittrich

Barbara Dittrich

Institute of Technical and Macromolecular Chemistry, Chair of Textile and Macromolecular Chemistry, RWTH Aachen University, 52074 Aachen, Germany

These authors contributed equally to this work.

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Daniel Haamann

Daniel Haamann

Institute of Technical and Macromolecular Chemistry, Chair of Textile and Macromolecular Chemistry, RWTH Aachen University, 52074 Aachen, Germany

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Pooyan Aliuos

Pooyan Aliuos

Department of Otolaryngology, Hannover Medical School, 30625 Hannover, Germany

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Doris Klee

Doris Klee

Institute of Technical and Macromolecular Chemistry, Chair of Textile and Macromolecular Chemistry, RWTH Aachen University, 52074 Aachen, Germany

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Ingo Nolte

Ingo Nolte

Small Animal Clinic, University of Veterinary Medicine Hannover, 30559 Hannover, Germany

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Thomas Lenarz

Thomas Lenarz

Department of Otolaryngology, Hannover Medical School, 30625 Hannover, Germany

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Günter Reuter

Günter Reuter

Department of Otolaryngology, Hannover Medical School, 30625 Hannover, Germany

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First published: 27 March 2013
Citations: 27

Abstract

The insertion of cochlear implants into the inner ear often causes inflammation and fibrosis inside the scala tympani and thus growth of fibrous tissue on the implant surface. This deposition leads to the loss of function in both electrical and laser-based implants. The design of this study was to realize fibroblast growth inhibition by dexamethasone (Dex) released from the base material of the implant [polydimethylsiloxane (PDMS)]. To prevent cell and protein adhesion, the PDMS was coated with a hydrogel layer [star-shaped polyethylene glycol prepolymer (sPEG)]. Drug release rates were studied over 3 months, and surface characterization was performed. It was observed that the hydrogel slightly smoothened the surface roughened by the Dex crystals. The hydrogel coating reduced and prolonged the release of the drug over several months. Unmodified, sPEG-coated, Dex-loaded, and Dex/sPEG-equipped PDMS filaments were cocultivated in vitro with fluorescent fibroblasts, analyzed by fluorescent microscopy, and quantified by cell counting. Compared to the unmodified PDMS, cell growth on all modified filaments was averagely 95% ±standard deviation (SD) less, while cell growth on the bottom of the culture dishes containing Dex-loaded filaments was reduced by 70% ±SD. Both, Dex and sPEG prevented direct cell growth on the filament surfaces, while drug delivery was maintained for the duration of several months. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 442–454, 2014.

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