Detection of pathogenic bacteria in milk and whey samples using a fluorescence resonance energy transfer aptasensor based on cerium oxide nanoparticles.

Herein, we present a facile and sensitive fluorescence resonance energy transfer (FRET) aptasensor for the detection of pathogenic bacteria, where antibiotic-functionalized cerium oxide nanoparticles were served as an energy donor and aptamer-modified gold nanoparticles (aptamer-AuNPs) were employed as an energy acceptor. To illustrate the feasibility of this strategy, () was examined. The strategy for the detection of bacteria as a target molecule is described using the FRET pair of azithromycin-functionalized CeO nanoparticles (Azm-CeONPs) and aptamer-AuNPs. The spectral overlap between these two nanoparticles and Azm and the aptamer binding on the surface of specifically provides the condition, which leads to the occurrence of the FRET phenomenon. In this way, a good linear correlation between the fluorescence intensity of Azm-CeONPs and concentration was obtained in the range of 10-1.5 × 10 cfu mL. The detection limit of the proposed method at a signal to noise ratio of 3 (3σ) was estimated to be 1.04 cfu mL. Further, the proposed method was applied to detect in real samples within 30 min, which indicates the applicability of the proposed method. This method could be used for other pathogenic bacterium recognition or synchronous detection by employing molecules that are particular to the desired bacteria.