Electrically Controlled Neurochemical Release from Dual‐Layer Conducting Polymer Films for Precise Modulation of Neural Network Activity in Rat Barrel Cortex

Implantable microelectrode arrays (MEAs) are important tools for investigating functional neural circuits and treating neurological diseases. Precise modulation of neural activity may be achieved by controlled delivery of neurochemicals directly from coatings on MEA electrode sites. In this study, a novel dual‐layer conductive polymer/acid functionalized carbon nanotube (fCNT) microelectrode coating is developed to better facilitate the loading and controlled delivery of the neurochemical 6,7‐dinitroquinoxaline‐2,3‐dione (DNQX). The base layer coating is consisted of poly(3,4‐ethylenedioxythiophene/fCNT and the top layer is consisted of polypyrrole/fCNT/DNQX. The dual‐layer coating is capable of both loading and electrically releasing DNQX and the release dynamic is characterized with fluorescence microscopy and mathematical modeling. In vivo DNQX release is demonstrated in rat somatosensory cortex. Sensory‐evoked neural activity is immediately (