Synthesis of active-site rich molybdenum-doped manganese tungstate nanocubes for effective electrochemical sensing of the antiviral drug (COVID-19) nitazoxanide.

Nitazoxanide (NTZ), a promising antiviral agent, is currently being tested in clinical trials as a potential treatment for novel coronavirus disease 2019 (COVID -19). This paper describes a one-pot hydrothermal synthesis to prepare molybdenum (Mo)-doped manganese tungstate nanocubes (Mo-MnWO NCs) for the electrochemical sensing of NTZ. The as-prepared Mo-MnWO NCs were characterized using various techniques such as XRD, Raman, FE-SEM, FE-TEM, and XPS to confirm the crystal structure, morphology, and elemental composition. The obtained results demonstrate that Mo doping on MnWO generates many vacancy sites, exhibiting remarkable electrochemical activity. The kinetic parameters of the electrode modified with Mo-MnWO NCs were calculated to be (Ks) 1.1 × 10 cm s and (α) 0.97, respectively. Moreover, a novel electrochemical sensor using Mo-MnWO NCs was fabricated to detect NTZ, which is used as a primary antibiotic to control COVID-19. Under optimal conditions, the electrochemical reduction of NTZ was determined with a low detection limit of 3.7 nM for a linear range of 0.014-170.2 μM with a high sensitivity of 0.78 μA μM cm and negligible interference with other nitro group-containing drugs, cations, and anions. The electrochemical sensor was successfully used to detect NTZ in the blood serum and urine samples and achieved high recoveries in the range of 94-99.2% and 95.3-99.6%, respectively. This work opens a way to develop high-performance sensing materials by exploring the introduction of defect engineering on metal tungstates to detect drug molecules for practical applications.