An experimental and theoretical aided 2D MoS2 nanoflowers strategy for rapid visual sensing of Gallic acid in food and clinical matrixes

Gallic acid (GA), an important phenolic component, is gaining popularity due to its biological and industrial applications. However, its rapid expansion can be hazardous, causing cancer and gene damage, making the design of a low-cost and fast GA sensor difficult. We used a single-step hydrothermal approach to synthesize MoS₂ nanoparticles for colorimetric detection of GA. The nanoparticles were analyzed using techniques like; UV–Vis spectroscopy, FT-IR spectroscopy, SEM, EDX and XRD. The optimization of key parameters such as MoS₂ concentration (2.0 mg), temperature (30 °C), and pH (7) resulted in a limit of detection (LOD) of 0.125 × 10⁻⁶ M with a dynamic range of 0.5 to 36 × 10⁻⁶ M. MoS₂ nanoflowers performed as nanozymes in the filter paper-based sensor, catalyzing 3, 3′, 5, 5′-tetramethylbenzidine (TMB) oxidation, while GA acted as an inhibitor to prevent further reaction progression. The detection was made feasible through capturing an image support by an ordinary smartphone and the steady-state kinetic study validated MoS₂ nanoflowers' affinity for sensing H₂O₂. The sensor performed well in real-world samples such as diet tea, green tea, water, blood serum, and urine, with recovery rates ranging from 93.2 % to 102.1 %. Density functional theory calculations were applied to provide an insight into GA-MoS₂ binding interactions and changes in electronic properties. With all of these merits, we believe MoS₂ nanoparticles can provide low-cost and portable filter paper-based strips as a sensing platform for visual assessment of GA.