Novel Ti₃C₂T_x/MWCNTs/UiO-66 with 2D/1D/3D mixed-dimensional heterostructures for enhanced electrochemical sensing of ofloxacin in aquatic products

Rationally engineered mixed‑dimensional heterostructures enable synergistic and interfacial effects that are inaccessible to single components. Here we construct a 2D/1D/3D Ti₃C₂T_x/MWCNTs‑COOH/UiO‑66 nanohybrid and deploy it as an electrocatalytic interface for the differential‑pulse‑voltammetric (DPV) detection ofloxacin in aquatic foods. In this architecture, 2D Ti₃C₂T_x MXene acts as a highly conductive scaffold, while 1D carboxyl-functionalized multi-walled carbon nanotubes (MWCNTs-COOH) are intercalated between MXene sheets to suppress restacking and build rapid electron pathways. The 3D metal-organic framework UiO-66, is anchored onto the MXene/MWCNTs network, providing abundant adsorption and recognition sites. resulting in hybrid materials with superior electrocatalytic activity. The mixed‑dimensional heterointerfaces promote fast charge transport and strong ofloxacin preconcentration. Under optimized conditions, the Ti₃C₂T_x/MWCNTs-COOH/UiO-66 modified electrochemical sensor demonstrated excellent performance for ofloxacin detection, delivering the wide linear range (0.04–50.0 μmol/L) and a low limit of detection of 0.018 μmol/L (S/N = 3). The sensor also exhibits excellent anti-interference, repeatability, reproducibility, and stability. Recoveries of 95.9%~110.0% and the agreement with a reference HPLC method in real samples analysis, substantiate its practical utility for monitoring ofloxacin residues in aquatic foods. This work illustrates a generalizable route to leverage mixed‑dimensional MXene/MOF architectures for signal amplification in electrochemical antibiotic sensing.