Highly sensitive detection of multiple antiviral drugs using graphitized hydroxylated multi-walled carbon nanotubes/ionic liquids-based electrochemical sensors.

Global outbreaks and the spread of viral diseases in the recent years have led to a rapid increase in the usage of antiviral drugs (ATVs), the residues and metabolites of which are discharged into the natural environment, posing a serious threat to human health. There is an urgent need to develop sensitive and rapid detection tools for multiple ATVs. In this study, we developed a highly sensitive electrochemical sensor comprising a glassy carbon electrode (GCE) modified with graphitized hydroxylated multi-walled carbon nanotubes (G-MWCNT-OH) and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6, IL) for the detection of six ATVs including famciclovir (FCV), remdesivir (REM), favipiravir (FAV), hydroxychloroquine sulfate (HCQ), cepharanthine (CEP) and molnupiravir (MOL). The morphology and structure of the G-MWCNT-OH/IL nanocomposites were characterized comprehensively, and the electroactive surface area and electron conductivity of G-MWCNT-OH/IL/GCE were determined using cyclic voltammetry and electrochemical impedance spectroscopy. The thermodynamic stability and non-covalent interactions between the G-MWCNT-OH and IL were evaluated through quantum chemical simulation calculations, and the mechanism of ATV detection using the G-MWCNT-OH/IL/GCE was thoroughly examined. The detection conditions were optimized to improve the sensitivity and stability of electrochemical sensors. Under the optimal experimental conditions, the G-MWCNT-OH/IL/GCE exhibited excellent electrocatalytic performance and detected the ATVs over a wide concentration range (0.01-120 µM). The limit of detections (LODs) were 42.3 nM, 55.4 nM, 21.9 nM, 15.6 nM, 10.6 nM, and 3.2 nM for FCV, REM, FAV, HCQ, CEP, and MOL, respectively. G-MWCNT-OH/IL/GCE was also highly stable and selective to the ATVs in the presence of multiple interfering analytes. This sensor exhibited great potential for enabling the quantitative detection of multiple ATVs in actual water environment.

A sensitive electrochemical sensor for environmental toxicity monitoring based on tungsten disulfide nanosheets/hydroxylated carbon nanotubes nanocomposite.

There has been growing concern about the toxic effects of pollutants in the aquatic environment. In this study, a novel cell-based electrochemical sensor was developed to detect the toxicity of contaminants in water samples. A screen-printed carbon electrode, which was low-cost, energy-efficient, and disposable, was modified with tungsten disulfide nanosheets/hydroxylated multi-walled carbon nanotubes (WS2/MWCNTs-OH) to improve electrocatalytic performance and sensitivity. The surface morphology, structure, and electrochemical property of WS2/MWCNTs-OH composite film were characterized by emission scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Raman spectroscopy, and electrochemical impedance spectroscopy. Grass carp kidney cell line was utilized as the sensor biorecognition element to determine the electrochemical signals and evaluate cell viability. The sensor was used to detect the toxicity of one typical contaminant (2,4,6-trichlorophenol) and two emerging contaminants (bisphenol AF and polystyrene nanoplastics). The 48 h half inhibitory concentration (IC50) values were 169.96 µM, 21.88 µM, and 123.01 µg mL-1, respectively, which were lower than those of conventional MTT assay, indicating the higher sensitivity of the proposed sensor. Furthermore, the practical application of the sensor was evaluated in chemical wastewater samples. This study provides an up-and-coming tool for environmental toxicity monitoring.