Aptamer modified magnetic nanoparticles coupled with fluorescent quantum dots for efficient separation and detection of Alicyclobacillus acidoterrestris in fruit juices

Abstract

Alicyclobacillus acidoterrestris greatly affects the quality of fruit juice products. In this study, we propose a new strategy that combines an aptamer and antibody with magnetic nanoparticles and fluorescence detection to effectively detect A. acidoterrestris in fruit juices. The aptamer-coated magnetic nanoparticles (MNP-APTs) were prepared for specific separation of target bacteria, and the antibody-stabilized quantum dots (QDs-Abs) were synthesized for fluorescence detection. For reverse detection of the target bacteria, we measured the residual quantum dot fluorescence signal in the system. The detection limit of the established method was 103 CFU/mL, and the entire detection process was completed within 90 min. The results demonstrate that the constructed MNP-APTs capture probe and QDs-Abs recognition probe could be successfully applied to the rapid separation and detection of A. acidoterrestris in apple juice, which provide a new idea for the detection of contaminated substances in juice production.