Highly Selective Cobalt-MOF/Vanadium Carbide MXene Hydrogel for Simultaneous Electrochemical Determination of Levothyroxine and Carbamazepine in Simulated Blood Serum

Abstract

The accurate and simultaneous detection of Levothyroxine (LT4) and carbamazepine (CBZ) in biological samples remains a critical challenge in biomedical sensing, given the need for high sensitivity, selectivity, and stability in complex biological environments. This work presents the synthesis and electrochemical characterization of a novel MOF-71/V₂C MXene-based hydrogel (Cobalt Metal-Organic Framework/Vanadium Carbide MXene) as an advanced sensor for the concurrent and simultaneous detection of Levothyroxine (LT4) and Carbamazepine (CBZ). The MOF-71/V₂C MXene-based Hydrogel is synthesized using a solvothermal technique and subsequent freeze-drying process. Structural characterization studies confirm a stable, porous interconnected layered architecture with a high surface area, facilitating effective interaction with target analytes. XRD (X-ray Diffraction) and CA (Contact Angle) analysis validate the crystalline and hydrophilic character of the material, respectively. The MOF-71/V₂C MXene-based hydrogel sensor exhibits a wide linear detection range (10 nM to 100 µM for LT4 & 10 nM to 500 µM for CBZ), excellent selectivity against prevalent interfering species, i.e., Dopamine, Tyrosine, glucose (GLU), urea, Mg²⁺, Ca²⁺, prevalent in biological fluids, and a low detection limit (LOD) of 5.6 nM for LT4 and 6.7 nM for CBZ. In addition, MOF-71/V₂C MXene hydrogel showed outstanding electrochemical stability and high reproducibility with RSDs of 1.65% for LT4 and 2.81% for CBZ, ensuring stable long-term performance. These results underscore the utility of the MOF-71/V₂C MXene-hydrogel as a high-sensitivity electrochemical sensor for therapeutic drug monitoring. Its highly hydrophilic and porous structure presents an electrochemical reaction-facilitating environment such that the sensor retains high sensitivity even in biologically complex matrices like blood serum. The adaptability of the hydrogel also presents favorable possibilities for incorporation in flexible and wearable electrochemical devices, presenting an important contribution in the area of biomedical sensing.