European Archives of Oto-Rhino-Laryngology

, Volume 269, Issue 4, pp 1111–1116 | Cite as

Oriented collagen as a potential cochlear implant electrode surface coating to achieve directed neurite outgrowth

  • Stefan Volkenstein
  • John E. Kirkwood
  • Edwina Lai
  • Stefan Dazert
  • Gerald G. Fuller
  • Stefan Heller


In patients with severe to profound hearing loss, cochlear implants (CIs) are currently the only therapeutic option when the amplification with conventional hearing aids does no longer lead to a useful hearing experience. Despite its great success, there are patients in which benefit from these devices is rather limited. One reason may be a poor neuron-device interaction, where the electric fields generated by the electrode array excite a wide range of tonotopically organized spiral ganglion neurons at the cost of spatial resolution. Coating of CI electrodes to provide a welcoming environment combined with suitable surface chemistry (e.g. with neurotrophic factors) has been suggested to create a closer bioelectrical interface between the electrode array and the target tissue, which might lead to better spatial resolution, better frequency discrimination, and ultimately may improve speech perception in patients. Here we investigate the use of a collagen surface with a cholesteric banding structure, whose orientation can be systemically controlled as a guiding structure for neurite outgrowth. We demonstrate that spiral ganglion neurons survive on collagen-coated surfaces and display a directed neurite growth influenced by the direction of collagen fibril deposition. The majority of neurites grow parallel to the orientation direction of the collagen. We suggest collagen coating as a possible future option in CI technology to direct neurite outgrowth and improve hearing results for affected patients.


Cochlear implant Hearing loss Spiral ganglion Electrode–neuron interface Directed neurite growth 



This work was supported by a BioX-grant of Stanford University to Drs. G.F., Frank Longo, and S.H., by Med-El Worldwide Headquarters Innsbruck, Austria, by the US National Institutes of Health grants DC06167 and P30 DC010363 to S.H., and by a postdoctoral fellowship of the Deutsche Akademie der Naturforscher Leopoldina (German Academy of Science, BMBF-LPD 9901/8-171) to S.V.

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Stefan Volkenstein
    • 1
    • 2
    • 3
  • John E. Kirkwood
    • 4
  • Edwina Lai
    • 4
  • Stefan Dazert
    • 3
  • Gerald G. Fuller
    • 4
  • Stefan Heller
    • 1
    • 2
  1. 1.Department of Otolaryngology, Head and Neck SurgeryStanford University School of MedicineStanfordUSA
  2. 2.Department of Molecular and Cellular PhysiologyStanford University School of MedicineStanfordUSA
  3. 3.Department of Otolaryngology, Head and Neck SurgeryRuhr-University Bochum, St. Elisabeth-HospitalBochumGermany
  4. 4.Department of Chemical EngineeringStanford UniversityStanfordUSA

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