Aptamer and Ru(bpy)(3)(2+)-AuNPs-based electrochemiluminescence biosensor for accurate detecting Listeria monocytogenes

As a widespread foodborne pathogen, Listeria monocytogenes (LM) can potentially cause a large number of food safety incidents, and the mortality rate of humans infected with this pathogen is relatively high. Thus, establishment of a fast and simple inspection technology is imperative. Herein, a solid-state electrochemiluminescence (ECL) biosensing switch system based on special ferrocene-labeled molecular beacon aptamer (Fc-MBA) has been developed for rapid detection of LM. The biosensor consisted of two main parts, an ECL substrate and an ECL intensity switch. ECL substrate was generated by modifying the complex of gold nanoparticle (AuNPs) and ruthenium (II) tris-(bipyridine) onto Au electrode, and an MBA labeled by Fc that acted as an ECL intensity switch. Moreover, in the presence of LM, the stem-loop structure of MBA could be opened and the ferrocene was kept away from ECL substrate, which was due to an obvious ECL intensity increment. The limit of detection was 5 CFU/mL, and satisfactory recoveries of 98.1-103.6% were observed. Thus, we propose a novel method for accurate and specific detection of LM.