Hierarchical molybdenum disulfide nanosheets based lateral flow immunoassay for highly sensitive detection of tetracycline in food samples.

• A sensitive biosensor that introduced MoS 2 as extraordinary probes was constructed to detect tetracycline. • Exfoliated nanosheets with large, middle, and small sizes and all exhibited excellent water-dispersibility and stability. • The versatile MoS 2 can label antibodies without the need for surfactant modification. • A very low limit of detection of 0.023 ng/mL was obtained for tetracycline detection. In this study, we report a simple approach for synthesizing three kinds of molybdenum disulfide (MoS 2) nanosheets with different sizes of large, middle, and small (which are defined as L -MoS 2 , M -MoS 2 and S -MoS 2) by an aqueous-phase exfoliation and differential-zone centrifugation (AE-DC) strategy, and for the first time explored the MoS 2 labeled antibodies (Abs) as probes for sensitive detection of tetracycline (TET) on lateral flow assays (LFAs). The hierarchical MoS 2 had uniform sizes (Average size: 366 ± 65.70 nm, 131 ± 24.39 nm and 55 ± 8.56 nm for L -MoS 2 , M -MoS 2 , and S -MoS 2 , respectively; thickness: 3 nm, 1 nm for and 0.5 nm for L -MoS 2 , M -MoS 2 and S -MoS 2 , respectively), and all exhibited excellent water-dispersibility and stability. Compared with M -MoS 2 and S -MoS 2 based LFAs, L -MoS 2 based LFA particularly displayed highly sensitive detection of TET due to the larger surface area and stronger color intensity. Under optimized experimental conditions, the developed L -MoS 2 -based immunosensor showed a great linear relationship over the range of 0.012–0.75 ng/mL in 15 min and a signal sensitivity up to 0.023 ng/mL for TET detection, which was at least 17-fold lower than traditional gold nanoparticles based LFA. The assay resulted in excellent specificity and reproducibility, and can be well-applied in milk, honey, and beef samples for monitoring TET. [ABSTRACT FROM AUTHOR]