A novel dual-mode Fluorescence/Colorimetric Aptasensor Based on NH2-MIL-88B(Fe)/CDs-Apt for Kanamycin Detection.

Kanamycin (KANA) is a veterinary drug residue that is highly scrutinized in food safety testing. In this study, a metal-organic framework-based aptamer-nanoenzyme (NH2-MIL-88B(Fe)/CDs-Apt) was introduced for the dual-mode detection of KANA. NH2-MIL-88B(Fe) catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H₂O₂ to form blue ox-TMB, thereby enabling colorimetric detection. As a fluorescence quencher, NH2-MIL-88B(Fe) quenches the fluorescence of CDs via photogenerated electron transfer (PET) or fluorescence resonance energy transfer (FRET) mechanisms. The detection limits were 0.716 fM (fluorescent) and 0.709 fM (colorimetric), respectively. The proposed aptasensor was successfully applied to the detection of KANA in eggs, honey, and lake water. This aptasensor demonstrates high sensitivity and accuracy, as well as broad application potential.