Electrochemical Sensor for the Determination of Methotrexate Based on MOF-Derived NiO/Ni@C-Poly(isonicotinic acid)

Abstract

A new electrochemical sensor based on NiO/Ni@C and poly(isonicotinic acid), PINA, is fabricated to determine an important chemotherapeutic drug, methotrexate (MTX). At first, a bare glassy carbon electrode (GCE) was modified by NiO/Ni@C; then, INA was electropolymerized at its surface. FT-IR, XRD, FE-SEM, EDS, elemental mapping, TEM, AFM, and BET techniques were used to characterize the nanomaterials. Following that, parameters affecting the sensor response, such as pH, amount of the electrocatalyst, electropolymerization cycles, and instrumental parameters, were optimized using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under the optimized conditions, a linear range was obtained from 0.02 to 2.5 μM with a detection limit of 7.2 nM. Repeatability was obtained with a relative standard deviation (RSD) of 2.4%, and reproducibility was obtained with an RSD of 6.2%. Finally, the sensor was tested in the presence of potential interference compounds and human blood plasma with acceptable responses.

Design and fabrication of electrochemical sensor based on NiO/Ni@C-Fe3O4/CeO2 for the determination of niclosamide

“…Ni-MOF was produced using the methods described in earlier literature 8 . To summarize, a solution was prepared by dissolving 1.4 mmol of Ni(NO 3 ) 2 ·6H 2 O, 0.70 mmol of trimesic acid, and 1.50 g of PVP in a mixed solvent consisting of ethanol, DMF, and water in a 1:1:1 ratio.…”

“…The intrinsic electrochemical sensing capabilities of unmodified electrodes are often hampered by slow reaction kinetics, inadequate sensitivity, and high overpotentials. These limitations can be effectively addressed through the strategic modification of the electrode surface with materials like metal oxides and metal–organic frameworks (MOFs), leading to demonstrably improved sensing performance 7 , 8 . Recent advancements in nanostructured metal oxides have yielded highly selective and cost-effective electrochemical sensors.…”

“…By tailoring the morphology, size, and composition of these metal oxide nanoparticles (MO NPs) through versatile synthesis methods, scientists have unlocked a diverse range of electrochemical properties. This fine-tuning empowers the MO NPs to exhibit enhanced catalytic activities, significantly boosting sensor performance 8 , 9 . Within the diverse landscape of metal oxides, nanoscale cerium oxide (CeO 2 ) has emerged as a particularly noteworthy material due to its unique properties.…”

“…Thermal calcination of MOF precursors offers a rapid route to fabricate carbon-coated metal oxide composites. This metallic/metallic oxide@carbon composite presents several compelling advantages, including enhanced catalytic activity due to the accessibility of active metal sites, tunable pore volume for optimized molecular transport, and a well-ordered architecture that promotes efficient catalytic processes 8 .…”

“…This optimized sensor boasts an impressive detection limit of 7.2 nM, consistent results, and resistance to interference from other substances. It even proved effective in real-world samples like blood plasma 8 . Miri et al .…”