Facile Electrochemical Microbiosensor Based on In Situ Self-Assembly of Ag Nanoparticles Coated on Ti3C2Tx for In Vivo Measurements of Chloride Ions in the PD Mouse Brain.

Chloride ion (Cl-), one of the most important anions in the brain, has been confirmed to participate in the pathological process of Parkinson's disease (PD). As such, the development of a reliable method for in vivo measurements of Cl- is extremely appealing, especially for understanding the pathogenesis of PD. We herein designed a facile electrochemical microbiosensor (ECMB), based on in situ self-assembly of Ag nanoparticles (Ag NPs) coated on Ti3C2Tx. The uniform nanosized Ag NPs were reduced by Ti3C2Tx by a simple dipping process, endowing the ECMB with excellent specificity toward Cl- detection and remarkably reproducible preparation process. Meanwhile, electro-oxidized graphene oxide was introduced as an inner reference, thus avoiding the environmental interference of the complicated brain systems to increase the determination accuracy. An extensive in vitro study revealed that the proposed ECMB would be a robust candidate for real-time monitoring of Cl- in the PD mouse brain with high selectivity, accuracy, and reproducibility. Moreover, the availability and reliability toward in vivo Cl- monitoring of the designed ECMB were well confirmed by comparing with the standard Volhard's method. Finally, by virtue of the successful employment of the developed detecting platform in the in vivo measurement of Cl- in the PD mouse brain, systematic analysis and comparison of the average levels of Cl- in the three regions including cortex, striatum, and hippocampus of brains from normal and PD model mice have been achieved.