Colorimetric detection of kanamycin based on analyte-protected silver nanoparticles and aptamer-selective sensing mechanism

Abstract

In this work, a novel colorimetric detection method for kanamycin (Kana), a widely used aminoglycoside antibiotic, has been developed using unmodified silver nanoparticles (AgNPs) as sensing probe. The method is designed based on the finding that the analyte (Kana) can protect AgNPs against salt-induced aggregation, and nucleic acid aptamers can decrease the risk of false positives through an aptamer-selective sensing mechanism. By use of the proposed method, selective quantification of Kana can be achieved over the concentration range from 0.05 to 0.6 μg mL−1 within 20 min. The detection limit is estimated to be 2.6 ng mL−1, which is much lower than the allowed maximum residue limit. Further studies also demonstrate the applicability of the proposed method in milk samples, revealing that the method may possess enormous potential for practical detection of Kana in the future.