Multifunctional microelectrode array (mMEA) chip for neural-electrical and neural-chemical interfaces: Characterization of comb interdigitated electrode towards dopamine detection

Microelectrode array platforms have attracted considerable interest owing to their ability to facilitate interactive communications between investigators and neuronal network. We herein present an integrated multifunctional microelectrode array (mMEA) chip harnessed with multiple measurement modalities of both neural-electrical and neural-chemical recordings to enable simultaneous monitoring of action potential and the level of the specific neurotransmitter. A dopamine sensor modality fabricated in interdigitated electrodes (IDE) fashion was realized and characterized, subsequently applied to trace dopamine exocytosis in PC12 cells cultured on such mMEA chip. Facile fabrication process leveraging electroplating technique to implement the regulation of gap width was investigated and resulted in preferred IDE configuration. Collection efficiency and amplification effect were systematically evaluated. The as-fabricated sensing device exhibited a favorable diffusion-determining behavior reflected by the steady state current output, and in virtue of this feature, to detect dopamine in connection with limit of detection at 0.62μM. The current signal was observed linear against the level of dopamine over the investigated concentration range with a resulting sensitivity of 0.096nAμM^-1.