Polymeric nanomaterials are gaining increased interest in medical applications due to the sustained release of bioactive agents. Within this study nanomaterials are fabricated using laser ablation of silver and copper in polymer-doped organic liquids thus allowing to produce customized drug release systems. A strategy is shown to determine the therapeutic window for cells relevant for cochlear implant electrodes, defined by the viability of L929 fibroblasts, PC12 neuronal cells, and spiral ganglion cells on different concentrations of silver and copper ions. The distribution of nanoparticles within the silicone polymer matrix is determined using transmission electron microscopy. Hexane doped with 1\% silicone resin is found to be an appropriate liquid matrix to fabricate a nanocomposite with a constant ion release rate. Silver ions of 10 µmol L−1 or copper ions of 100 µmol L−1 cause a suppression of tissue growth without inhibiting neuronal cell growth. The copper nanoparticle content of 0.1 wt\% of the silicone composite releases ion concentrations which fit the therapeutic window.