Graphdiyne oxide enhances the stability of solid contact-based ionselective electrodes for excellent in vivo analysis

Abstract

Quantitively and stably tracking ion dynamics in the living brain of animals is essential to understanding many physiological and pathological processes. Solid-state ion-selective electrodes (ISEs) are powerful tools for monitoring the dynamic change of ions at physiological concentration range; however, the unintentional accumulation of an aqueous layer at the ion selective membrane/ solid contact interface compromises the electrode potential stability, limiting its in vivo application. Here, using manganese dioxide (MnO2) and potassium ISE (K+-ISE) as model solid contact and ISEs, we demonstrate for the first time that graphdiyne oxide (GDYO) can enhance the potential stability of solid contact-based ISEs. Our results suggest that the intrinsic structural and hydrophobic features of GDYO, plays a key role in impeding and stabilizing the formation of water layer. With GDYO-MnO2 acting as the solid contact, the K+-ISE displays an excellent short-term potential stability and maintains great selectivity, achieving reliable K+ sensing at the animal level. The GDYO-based strategy is generalizable to different ISEs and does not require complicated processing steps, paving an exciting opportunity for in vivo ion recognition and sensing.