Iridium Oxide (IrOx) serves as adhesion promoter for conducting polymers on neural microelectrodes

Conducting polymers (CPs) as functional coatings on microelectrodes enable the realization of neural probes with superior electrical properties compared to metallized probes. Besides significantly lower impedance and enhanced charge delivery capacity, CPs further feature the possibility to release drugs from their bulk which can be done exclusively from these materials. Thus the usage of CPs at the neural interface for recording or stimulation of neural tissue is of great interest. A drawback that has however been observed at usage of conducting polymers in vitro and in vivo is the weak adhesion of the polymer to the substrate which ultimately leads to delamination of the coatings. This effect has limited the applicability of polymer coatings on neural probes despite their overall promising potential. In our study we address this gap by introducing Iridium Oxide (IrOx) as adhesion promoter for long-term stabilization of CP films. Exaggerated stressing protocols revealed superior adhesion of the polymer to the rough structure of IrOx and electrochemical measurements indicated unrestricted polymer functionality. With the herein proposed strategy a major obstacle of using conducting polymers at the neural interface could be efficiently targeted and thus applicability of CPs for neural interfaces can be extended in future electrode generations.