Abstract
Abstract In this work, a fluorescence aptasensor has been developed to detect trace chloramphenicol based on FRET and exonuclease-assisted target recycling. Firstly, the composite probe for CAP was prepared through the immunoreactions between the capture probe based on dsDNA antibody labeled on Fe 3 O 4 @Au nanoparticles and the nanotracer using double strand aptamer (aptamer hybrid with its complementary DNA) labeled on core-shell SiO 2 @Au. When the composite probe solution was mixed with CAP, the aptamer on the nanotracer preferentially bounded with CAP, and then released cDNA-SiO 2 @Au and CAP-Apt complex to the supernatant. This is because anti-DNA on capture probes can’t recognize the ssDNA. The exonuclease I (Exo I) added into the supernatant can further digest the aptamer-CAP from the 3′-end of aptamer and release CAP again, which can further participate in new cycle to react with the probes. The supernatant containing numerous SiO 2 @Au could efficiently quench the fluorescence response of CdSe QDs by FRET. Experimental results showed the CAP detection owning a linearity range of 0.001–10 ng mL −1 and detection of limit (LOD) of 0.0002 ng mL −1 . Besides, the results of our method for CAP detection in the fish samples agreed well with those from ELISA, verifying its accuracy and reliability.
Published Version
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