On-site rapid detection of Listeria monocytogenes in dairy products using smartphone-integrated device-assisted ratiometric fluorescent sensors

The contamination of Listeria monocytogenes (L. monocytogenes) in dairy products poses a significant risk to human health. It is urgent to develop on-site rapid strategy to reduce associated threats. We employed carbon dots (CDs) and silicon nanoparticles (SiNPs) as energy donors and acceptors respectively. The CDs and SiNPs were functionalised with vancomycin and aptamers correspondingly, leading to the establishment of ratiometric fluorescent sensor. With a portable smartphone-integrated device, the ratios of blue/green values from the colour images depended on L. monocytogenes concentrations for quantification. The sensors were demonstrated for monitoring L. monocytogenes in dairy products within 30 min.