Fe‐MXene Nanozyme for Dual‐Mode Colorimetric–SERS Sensing of Glucose With Mechanistic Insights Into Catalysis and Signal Enhancement

ABSTRACT

The development of colorimetric and surface‐enhanced Raman spectroscopy (SERS) dual‐mode analytical platforms based on nonnoble‐metal substrates is of considerable significance. However, the underlying mechanisms governing enzyme‐mimetic catalysis and SERS enhancement in nonnoble‐metal‐based systems remain insufficiently understood. In this work, the Fe‐MXene nanozyme was synthesized via a self‐reduction strategy. Enzyme‐like catalytic behavior and SERS enhancement performance were systematically elucidated by correlating the structural features of Fe‐MXene with its catalytic efficiency and signal amplification capability, governed by the Fenton‐like reactions and chemical enhancement mechanisms. On this basis, a dual‐mode sensing platform was developed for glucose determination. Glucose was enzymatically oxidized by glucose oxidase to generate hydrogen peroxide, which triggered Fe‐MXene‐catalyzed oxidation of 3,3′,5,5′‐tetramethylbenzidine (TMB) into a blue product, which exhibits distinct optical and Raman signatures. The sensor showed a linear response to glucose concentrations over 0.01–1.0 mM (colorimetric) and 0.01–0.8 mM (SERS), with detection limits of 14.2 µM (colorimetric) and 4.67 µM (SERS). Practical applicability was validated by glucose analysis in real samples, yielding satisfactory recoveries of 95.8%–106.5%. In addition, the Fe‐MXene nanozyme exhibited excellent stability, signal uniformity, and reusability. This work presents a simple, cost‐effective, and reliable dual‐mode sensing strategy for glucose detection, highlighting its potential in advanced biosensing applications.