Carbon Nanotube Array-Based Flexible Multifunctional Electrodes to Record Electrophysiology and Ions on the Cerebral Cortex in Real Time

Electrophysiology and neurochemicals such as Ca 2+ , K + , and Na + on the cerebral cortex can synergistically reflect the neurophysiological states. Transparent electrodes have been reported to record electrocorticography (ECoG) and image Ca 2+ on the cerebral cortex surface. However, Ca 2+ imaging is unable to track extracellular changes correlated with neural activities such as anesthesia, and imaging techniques to monitor K + and Na + are yet unavailable. Here, a flexible multifunctional electrode (FME) based on carbon nanotube array is presented to record ECoG and extracellular ions of Ca 2+ , K + , and Na + . The FME exhibits both lower impedance and higher capacitance than that of conventional gold electrodes. It simultaneously shows stable ion-sensing performance and long-term biocompatibility. The FME realizes multi-model recording of ECoG and extracellular ions on the cerebral cortex surface of rats, providing an effective detection method for brain science.