Platinum is a commonly used electrode material within neuronal electrodes, e.g. the cochlear implant (CI). A reduction of the distance between spiral ganglion neurons and the platinum contacts of the CI would be favorable in order to obtain a higher signal resolution. This can be achieved by inducing dendrite growth towards the electrode by the release of neurotrophines or neuroprotective drugs from the electrode.
Nanoporous platinum (NPPt) offers good electrochemical properties, a high surface area and good results within cell culture investigations. In order to accomplish a high drug loading we embodied nanoporous silica nanoparticles (NPSNPs) into the pore-system of the platinum. Those particles exhibit a large and permanent pore volume and, in contrast to platinum, a high versatility with regard to easily adjustable surface properties.[2,3]
A hard template approach was used, leading to the pore structure of the platinum, utilizing silica-polystyrene core-shell nanoparticles as template particles. After the electrochemical deposition of platinum, polystyrene was removed. SEM investigations showed the successful synthesis of the desired composition. Current work focuses on the characterization of this material and its biocompatibility.
This new hybrid material has the potential of combining the favorable properties of nanoporous platinum and nanoporous silica. Leading to a material with excellent electrochemical behavior simultaneously with a large pore volume and variety of possible surface modifications.
This work was supported by the DFG Cluster of Excellence EXC 1077/1 "Hearing4all".