Ratiometric fluorescence aptasensor based on structure-switching-triggered mimetic enzyme activity for sensitive detection of enrofloxacin

A structure-switching-triggered aptasensor was constructed based on carbon dots (CDs) to detect enrofloxacin (ENR). CDs-functionalized aptamer and two complementary chains (cDNA1 and cDNA2) modified by hemin monomer were self-assembled as sensor. The peroxidase-mimicking activity of hemin monomer can catalyze the oxidation of o-phenylenediamine to form 2,3-diaminophenazine (oxOPD) with yellow fluorescence. Simultaneously, during to the occurrence of fluorescence resonance energy transfer, the fluorescence of CDs was quenched. The detection linear range of ENR is 0.1–12 ng mL −1 , and the detection limit is 40.7pg mL −1 . Furthermore, the aptasensor demonstrated high accuracy and repeatability for the detection of actual aquatic product samples.