Ultra‐sensitive electrochemical immunosensor based on 2D vanadium diselenide (VSe₂) for efficient detection of pathogens: <scp><i>Salmonella Typhimurium</i></scp>

Layered transition metal dichalcogenides (TMDs), with an extensive surface area, intriguing tunable electrical and optical features, and a distinctive Van der Waals layered structure, yield outstanding sensing properties. Essentially, most TMDs originally existed in the crystallographic phase of a 2H trigonal prismatic structure, which is semiconducting in nature with poor electrocatalytic activity. In contrast, vanadium diselenide (VSe₂) with its metastable metallic 1 T octahedral crystal structure has been proven to be an outstanding electrode material, embracing exceptional electrocatalytic behavior for various electrochemical (EC) applications. However, practically, VSe₂ has hardly ever been explored in the field of biosensing technology. This study presents a novel EC biosensor based on the antibody of Salmonella Typhimurium (Anti-ST) immobilized on VSe₂-supported Indium tin oxide (Anti-ST/VSe₂/ITO) for quantitative and efficient Salmonella Typhimurium (ST) detection. The Anti-ST/VSe₂/ITO bioelectrode displayed a linear relationship with ST concentration (1.3 × 10-10⁷ CFU/ml) with a limit of detection (LOD) (0.096 CFU/ml) that is lower than previously reported ST biosensors and impressively high sensitivity (0.001996 μA.mL/CFU). Furthermore, the proposed electrode's electroanalytical activity was evaluated in spiked sugarcane juice, demonstrating distinguished applicability for specific ST detection in real samples.