Laser-Induced MXene/PVDF Nanofibrous-Based Ion-Selective Electrode Sensor for Continuous Monitoring of NA⁺ and K⁺Ions in Sweat

This study presents a novel ion-selective electrode (ISE) sensor that combines laser-induced TiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> nanoparticles on MXene/PVDF composite nanofiber mats to enable stable potential response and real-time monitoring of Na <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> and K<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> ions in sweat. This sensor has achieved high performance by the synergistic effect of TiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> NPs from MXene and PVDF converted laser-induced graphene electrode, which shows large electrochemical surface area and hydrophobicity, to enhance the double-layer capacitance and minimize potential drift. The developed ISE showed excellent ion selectivity and stability (0.04mV/h and 0.08mV/h), and recorded a sensitivity close to the Nernst sensitivity of 45 mV/decade and 56.6 mV/decade for Na<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> and K<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>, respectively. The developed sensor with fast response and high accuracy is highly promising and can be applied to non-invasive wearable health monitoring systems.