Electrochemically Exfoliated WS₂ Nanosheets for the Electrochemical Impedimetric Detection of NADH

Abstract

In this work, exfoliated WS2 nanosheets were synthesized using a two‐electrode‐configured electrochemical exfoliation method and they were used as a potential material for the detection of NADH. Using screen‐printed carbon electrodes (SPCEs) as a sensing platform, exfoliated WS2 nanostructures (ex‐WS2) were drop‐casted and their electrocatalytic activity was studied in the presence of NADH. The electrochemical impedance spectroscopy (EIS) was applied as a sensing tool to achieve superior sensing performance towards NADH. At the optimized DC bias value of 0.4 V, the developed NADH sensor shows linear calibration plots in the ranges of 2 to 2048 μM. From the calibration data, the sensitivity value was found to be 36.875 Ω log([NADH])−1 with the limit of detection (LOD) value of 57 nM. In addition to that, it also exhibited very high selectivity in the presence of other possible interfering species, suggesting that the present exfoliated WS2‐modified SPCE‐based sensing platform could be used for the impedimetric label‐free monitoring of NADH in various fields.

Polytyrosine-Coated Paper Electrode for Sensitive and Selective Sensing of NADH

“…Toward the manufacture of these electrodes, paper is a unique material that offers several advantages over others, and paper analytical devices satisfy the WHO’s ASSURED criteria for diagnostic devices. , Paper is biofriendly and offers printability, impregnability, porous structure, and filtering ability, and it also facilitates lateral flow. Thus, paper has been explored as a substrate for the fabrication of disposable, miniaturized, and user-friendly 3-in-1 paper electrodes (PE) with working, counter, and pseudoreference electrodes. − The fabrication of PEs and their surface morphological studies, as well as their electrochemical sensing performance, were detailed in a previous publication. ,− Briefly, PE with a 3-in-1 electrode (working, counter, and reference electrodes) was developed by introducing hydrophobic boundaries and hydrophilic patterns on the chromatography paper through photolithography. In the following, electrode patterns were stamped onto the desired area.…”

“…These methods demonstrated sensitivity; however, they are always connected with numerous drawbacks, such as sophisticated and expensive instrumentation, intricate sample preparations, high cost per test, and minimal analytical flexibility. The past decades have also witnessed the development of a wide range of electrochemical (amperometric, potentiometric, and impedimetric) sensors for NADH detection. − Undoubtedly, NADH detection using electrochemical sensors offers several advantages, such as cost-effectiveness, rapid analysis, minimal sample volume, excellent selectivity, and sensitivity . Toward the successful electrochemical sensing of NADH, the crucial factors being considered are the electrocatalytic activity and response time of electrodes, the selectivity and sensitivity of NADH over interfering biomolecules, and the reversibility of the biosensor designed. ,, …”

Unleashing the potential of tungsten disulfide: Current trends in biosensing and nanomedicine applications

“…Nonetheless, mechanically exfoliated materials lacked size and thickness uniformity across large areas, making the mechanical exfoliation technique inadequate for large-scale production [ 26 , 27 ]. As an alternative exfoliation approach of WS 2 , liquid-based exfoliation, including solvents assistance exfoliation [ 32 ], lithium intercalation approaches [ 33 , 34 ], and electrochemical exfoliation [ 35 , 36 ] have been widely relied on due to their simplicity, low cost, and high quality [ 37 ]. Following these approaches, larger nanoflakes in solution were performed, yet with difficult thickness and lateral size controls [ 38 ].…”

Functional Ink Formulation for Printing and Coating of Graphene and Other 2D Materials: Challenges and Solutions

“…Ion accumulation and the generation of gases then cause the expansion/detachment of TMD layers. [ 134 ] One big challenge in electrochemical exfoliation of the TMDs is the low conductivity of their bulk material, as most of the applied potential will be used to overcome the huge resistance. To address this problem, conductive additives are usually added to the powders of the TMDs’ parent crystal, and conductive monoliths are made and used for their electrochemical exfoliation.…”