Lateral flow biosensor for DNA extraction-free detection of Salmonella based on aptamer mediated strand displacement amplification.

Convenient and sensitive point-of-care rapid diagnostic tests for food-borne pathogens have been a long-felt need of clinicians. Traditional approaches such as culture-based methods have good sensitivity and specificity, but they tend to be tedious and time-consuming. Herein we present a simple and sensitive aptamer based biosensor for rapid detection of Salmonella enteritidis (S. enteritidis). One of the aptamers specific for the outmembrane of S. enteritidis was used for magnetic bead enrichments. Another aptamer against S. enteritidis was used as a reporter for this pathogen, which was amplified by isothermal strand displacement amplification (SDA) and further detected by a lateral flow biosensor. As low as 10(1) colony forming unit (CFU) of S. enteritidis was detected in this study. Without DNA extraction, the reduced handling and simpler equipment requirement render this assay a simple and rapid alternative to conventional methods.