Enzymatic Electrochemical Biosensor from Eu‐Doped SnO2 Embedded in MXene for High Performance Sensing Lactate

Abstract In this work, Eu 3+ ‐doped SnO 2 nanoparticles are prepared and embedded into MXene (Ti 3 C 2 ) laminates, and Ti 3 C 2 @Eu‐SnO 2 composites are obtained. Cyclic voltammetry (CV) and scanning electron microscopy (SEM) characterization show that the composites have excellent electrochemical properties and unique morphology. The electrochemical impedance spectroscopy (EIS) and Fourier transform infrared spectrometer (FTIR) results of lactate oxidase (Lox) immobilized on Ti 3 C 2 @Eu‐SnO 2 indicate that Eu‐SnO 2 , Ti 3 C 2, and Lox have a good hybrid coordination and biocompatibility. The enzymatic electrochemical biosensor constructed with Ti 3 C 2 @Eu‐SnO 2 /Lox on glassy carbon electrode (GCE) reveals an excellent linear relationship in the lactate concentration ranging from 1.0×10 −9 to 1.0×10 −4 mol L −1 . It has a low detection limit of 3.38×10 −10 mol L −1 and high sensitivity of 4.815 mA nmol −1 L cm −2 . Furthermore, the fabricated biosensor has a reasonable recovery rate for determining lactate in human serum.