Rapid and sensitive multimode detection of Salmonella typhimurium based on the photothermal effect and peroxidase-like activity of MoS2@Au nanocomposite

Abstract

Dot-filtration immunoassays (DFIAs) are powerful tools for simple and rapid field detection; however, the relatively poor sensitivity and accuracy of DFIAs limit their use in practical applications. A multimode dot-filtration immunoassay (MDFIA) was proposed for the sensitive, accurate and rapid detection of the target (Salmonella typhimurium) using the intrinsic color, peroxidase-like activity and photothermal effect of molybdenum disulfide-Au (MoS₂@Au). The critical performance parameters of MDFIA were analyzed. Salmonella typhimurium was selected to be the representative target. Corresponding to the intrinsic color, peroxidase-like activity and photothermal effect of MoS₂@Au, the limit of direct visual detection, catalytic coloration, and quantitative analysis were 10³ CFU mL⁻¹, 10² CFU mL⁻¹, and 10² CFU mL⁻¹, respectively. The detection sensitivity of MDFIA obtained by catalytic coloration and quantitative analysis was about one order of magnitude higher than that of direct visual detection. The detection accuracy was greatly improved through the mutual monitoring of three methods. The entire detection procedure, including sample preparation, required only 25 min. The MDFIA was successfully validated with different foodstuffs, demonstrating its application prospects in detection of foodborne pathogens in food safety, environment monitoring, and clinical testing.