Vanadium Disulfide Nanosheet Boosts Optical Signal Brightness as a Superior Enzyme Label to Improve the Sensitivity of Lateral Flow Immunoassay

The color-enzyme lateral flow immunoassay (LFIA) has attracted widespread attention to expand the detection range and improve sensitivity via amplifying the color signal after catalyzing the substrate. As a kind of layered transition-metal dichalcogenide ( TMD), the vanadium disulfide nanosheet (VS2NS) possesses superior peroxidase-like catalytic activity. Here, a VS2NS was applied as an enzyme label in the LFIA to detect 17 ss-estradiol (E2). Compared to natural horseradish peroxidase, the VS2NS expresses a more prominent enzyme catalytic performance, stability, and adsorption ability. Under optimal conditions, the calculated limit of detection (cLOD) of the VS2NS-based LFIA is 0.065 ng mL(- 1) for E2, which is sixfold lower than that of the optimized colloidal nanoparticle-based LFIA (cLOD = 0.406 ng mL(-1))(.) Besides, the detection linear range of the VS2NS-based LFIA can be widened by 1.5 times after the catalytic reaction. Moreover, the VS2NS-based LFIA exhibits excellent practicability in real sample detection. Simultaneously, this study helps open up the application of the VS2NS in the trace analysis of LFIAs, which can broaden TMDs' scope of application and better show their properties of color enzymes.