An Electrochemophysiological Microarray for Real‐Time Monitoring and Quantification of Multiple Ions in the Brain of a Freely Moving Rat

Abstract Herein, we present an electrochemophysiological microarray (ECPM) for real‐time mapping and simultaneous quantification of chemical signals for multiple ions in the deep brain of a freely moving rat, in which microelectrode arrays were developed for direct determination of multiple ions using open‐circuit potentiometry. Specific recognition ionophores were synthesized and optimized for determination of K + , Ca 2+ , Na + and pH. A reference electrode was also developed to avoid interferences in the brain. The microarrays were successfully applied in real‐time monitoring and quantification of ions in a live brain. The extra current‐free potentiometry allowed mapping and biosensing of chemical signals, together with recording of electrical signals in the whole brain without cross‐talk, for the first time. Furthermore, the ECPM provided a platform for real‐time monitoring of the dynamic changes of multiple ions in the deep brain of freely moving rat during a seizure.