Crumpled Ti₃C₂Tₓ MXene electrodes with tunable surface chemistry for high-performance and selective electrochemical biosensing

Crumpled Ti₃C₂Tₓ MXene-modified glassy carbon electrodes (GCEs) were engineered and analyzed to elucidate how surface chemistry and nanoscale morphology jointly govern selective biomolecule detection. The study integrates experimental electrochemical measurements and COMSOL Multiphysics modeling to decode charge-transfer and adsorption mechanisms for ascorbic acid (AA), dopamine (DA), uric acid (UA), and acetaminophen (ACA). The optimized crumpled MXene (10 nm amplitude, 10 nm layer thickness) exhibited superior sensitivity (0.77–0.82 µA µM⁻¹) and detection limits of 0.6–0.9 µM across 10–200 µM concentration ranges. High surface area (150 m² g⁻¹) and abundant –OH/–O terminations promoted π–π stacking and hydrogen bonding, enhancing analyte adsorption and electron transfer. Computational modeling, coupling Nernst–Planck and Butler–Volmer kinetics, predicted diffusion coefficients (1.2 × 10⁻⁵ cm² s⁻¹) and steady-state response times (1.47–2.38 s) that closely matched experimental results. Competitive adsorption caused only 5–8% sensitivity loss in multicomponent systems, while selectivity tests demonstrated < 2.5% current variation in the presence of interferents such as glucose or citric acid. These findings reveal a synergistic interplay between MXene surface functionality and crumpled morphology, offering a predictive framework for designing robust, high-performance electrochemical biosensors suitable for complex biological and food matrices.