Ultrasensitive detection of Listeria monocytogenes using a ratiometric fluorescence aptasensor in food products

Listeria monocytogenes (LM) is a foodborne pathogen known for its potential to cause serious infections, posing a considerable risk to food safety and endangering public health as well as the broader social economy. Here, we developed a novel switch-conversional ratiometric fluorescence aptasensor enabling ultrasensitive detection of LM by utilizing the Förster resonance energy transfer (FRET) phenomenon mediated by amplicon fragments, which were generated from the exponential amplification reaction (EXPAR). This biosensor integrates EXPAR for signal enhancement with aptamer recognition, facilitating ultra-sensitive detection of LM. Under optimized parameters, this biosensor reaches an impressive detection limit of 0.56 × 10° CFU/mL, along with a wide linear interval extending from 1.0 × 10 1 to 1.0 × 10 6 CFU/mL. Moreover, the biosensor demonstrates the capability to detect LM in spiked real food samples, achieving recovery rates that range from 87.1% to 101.9%, thereby underscoring its reliability and accuracy. Overall, this research demonstrates significant promise for the advancement of highly sensitive detection systems for foodborne pathogens.