Hearing loss is associated with significant challenges in society. If deafness is caused by hair cell loss in the inner ear, a cochlear implant can partially restore hearing. One critical issue is the relatively large gap between the electrode and the spiral ganglion neurons that get stimulated. For that a growth factor-based drug delivery system will be installed on the cochlear electrode to reduce the distance. This system is built on nanoporous silica nanoparticles, neurotrophin 3, brain-derived neurotrophic factor, a polymer coating and silicone.