A multimode dot-filtration immunoassay (MDFIA) was established for rapid and accurate detection of the target (Salmonella typhimurium), which was based on the intrinsic color, peroxidase-like activity and photothermal effect of molybdenum disulfide (MoS2). Obviously, multimode detection can improve detection accuracy compared to the direct visual detection in test strips. A thermal imaging camera was used as detector to record the temperature change (ΔT) of MoS2 and establish the standard curve of ΔT and the concentration of Salmonella typhimurium to realize quantitative determination. The main parameters that affect the analytical performance of MDFIA were optimized. Under the optimal experimental conditions, the limit of detection (LOD) of photothermal detection reached 102 CFU mL-1 and was one order of magnitude lower than the limit of direct visual detection and catalytic color development detection (103 CFU mL-1). The accuracy and analytical sensitivity were enhanced by intrinsic peroxidase-like activity and the huge photothermal effect of MoS2. Moreover, this method exhibited high selectivity, good repeatability, and acceptable stability and the entire process was simple to be accomplished in 30 min, which generally meets the need of rapid detection. The successful implementation in real samples with the recovery being between 99.5 and 119.2% showed that it could be used as a promising quality control strategy for detection of other foodborne pathogens. The peroxidase-like activity and excellent photothermal effect of MoS2 was used to develop a multimode dot-filtration immunoassay for rapid detection of Salmonella typhimurium.
Keywords: MDFIA; MoS2; Peroxidase-like activity; Photothermal effect; Salmonella typhimurium.