Bioactive cochlear implant electrodes with functionalised calcium phosphate nanoparticles

Introduction:

Quality of transmission between spiral ganglion cells and the cochlea electrode essentially influences hearing outcome after cochlea implantation. Calcium phosphate nanoparticles (CaP-NP) could generate a bioactive surface of the electrode and could possibly thus being used as a tool for active transport of proteins, DNA, RNA or drugs into the inner ear. However, potential interactions between nanoparticles used as coating and inner ear cells are still not well known.

Methods:

To address this issue, DNA-loaded CaP-NP were plated on cochlea electrodes and characterised by scanning electron microscopy and x-ray-spectrometry. Secondly, glass cover slips were coated with CaP-NP in a layer-by-layer method combined with polylysine. Interaction between CaP-NP and inner ear cells was analyzed via immunhistochemical staining of inner ear cells of newborn rats.

Results:

Electrophoretic plating on CI-electrodes was feasible. However, only minor concentrations of CaP-NP could be attached. In contrast, a layer-by-layer method allowed higher concentrations of CaP-NP to be precipitated on the surface. Immunhistochemical staining of the inner ear cells revealed adequate biocompatibility of CaP-NP including non-neural cell proliferation and axonal sprouting of inner ear cells.

Discussion:

Coating surfaces with functionalised nanoparticles is a feasible and successful method. A layer-by-layer method enables plating of higher amounts of CaP-NP and thus more efficient transport of proteins, DNA, RNA, or drugs. CaP-NP show sufficient biocompatibility towards inner ear cells.

Publication History

Publication Date:
23 April 2019 (online)