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

• A colorimetric method for kanamycin detection based on analyte-protected and aptamer-selective mechanism has been proposed.
• The testing procedure is facile and the whole detection process can be completed within 20 minutes.
• A linear range from 0.05 to 0.6 μg mL−1 with a detection limit of 2.6 ng mL−1 has been obtained.

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.

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