Simultaneous Determination of Glutamate and Calcium Ion in Rat Brain during Spreading Depression and Ischemia Processes

In vivo chemical analysis is an important aspect in exploring brain functions. Brain function realization depends on multiple chemical molecules working together. The determination of one single chemical substance is difficult to clarify the signal transduction and disease occurrence. Thus, it is particularly important to simultaneous determination of multiple biological species in the brain. In this study, we designed and constructed a dual-functional electrochemical biosensor for simultaneous detection of glutamate and Ca ²⁺ . Pt-microelectrode, jointly decorated by GluOx and Pt NPs, served as an amperometric recording channel for glutamate. Meanwhile, the all-solid-state Ca ²⁺ selective microelectrode (Ca-ISME) was employed as a potentiometric recording channel for Ca ²⁺ . The dual function microelectrode (DFME) biosensor was developed for simultaneous monitoring glutamate and Ca ²⁺ without crosstalk between the signals. The DFME biosensor showed good selectivity towards common interferences, as well as low detection limits (0.5 μM for glutamate and 1 μM for Ca ²⁺ ), which met the needs for in vivo analysis. Finally, the developed biosensor was successfully applied to real-time monitoring of glutamate and Ca ²⁺ in live rat brain during spreading depression (SD) and ischemia processes. This study provided a simple and effective approach for in vivo analysis of two or more chemical substances.