Engineering of silver nanoparticle-decorated and p-phenylenediamine-functionalized Ti₃C₂T_x MXene hybrid sensor for electrochemical detection of levofloxacin

This study introduces a novel hybrid electrochemical sensor based on Ti₃C₂T_x MXene nanostructures, offering enhanced and practical sensing performance. A silver nanoparticle-decorated, p-phenylenediamine-functionalized Ti₃C₂T_x MXene (Ag NPs/PPD-MXene) hybrid was engineered following simple two-step fabrication route consisting of PPD anchoring through alkalization followed by direct deposition of Ag NPs on the Ti₃C₂T_x MXene surface, specifically for the electrochemical detection of levofloxacin (LEVO). Cyclic voltammetry analysis reveals that the sensor response directly correlates with LEVO concentration, indicating clear Faradaic behavior. The linear relationship between the square root of the scan rate and response suggests a diffusion-controlled electrochemical process. DPV results show pH 2 as the optimal condition, with performance decreasing at higher pH levels. The sensor exhibits strong selectivity despite interferents and has high sensitivity, with a detection limit as low as 10 µM. Additionally, the sensor features a wide dynamic range from 10 µM to 2 mM, enabling reliable quantification across mid-to-high LEVO concentrations. The observed performance results from the unique chemical structure that allows numerous binding sites for LEVO detection through hydrogen bonds, non-covalent π–π interactions, and coordination bonds. Overall, the straightforward fabrication, robust performance, and broad concentration range highlight the practical value of this MXene-based sensing platform.