High-performance Pt/Ti₃C₂T_x MXene based graphene electrochemical transistor for selective detection of dopamine

Accurate measurement of dopamine (DA) is of great significance for human health monitoring and disease prevention. Herein, two-dimensional Ti₃C₂T_x MXene with high performance was prepared by layer liquid exfoliation method and used for the modification of gate electrode. The glassy carbon electrode (GCE) modified with Pt/Ti₃C₂T_x was used as the gate, and assembled with monolayer graphene channel to form a complete transistor device. The device combines the amplification effect of transistors, good electrical conductivity of Ti₃C₂T_x MXene and excellent catalytic properties of Pt nanoparticles, showing a low detection limit (50 nM) and a wide detection concentration range (50 nM-9 mM) of DA. Ti₃C₂T_x MXene not only provides a large number of attachment sites for the deposition of Pt nanoparticles, but also improves the electrical conductivity and hydrophilicity of the electrode material, thus enhancing the sensitivity of the device and facilitating the penetration of the solution to be measured. In addition, Ti₃C₂T_x MXene is negatively charged, it has a certain electrostatic adsorption effect on protonated DA and electrostatic repulsion effect on negatively charged interfering substances. As a result, the device exhibits good selectivity, which provides a great application prospect for the construction of DA sensing platform.