Aptamer act as fluorescence switching of bovine serum albumin stabilized gold nanoclusters for ultrasensitive detection of kanamycin in milk.

• A novel fluorescence switching aptasensor for ultrasensitive detection of Kana was developed. • Aptamer as fluorescence switching was simple to fabricate. • The constructed aptasensor showed high selectivity and accuracy. • The limit of detection, accuracy and recovery rate of the developed fluorescence aptasensor were satisfied. We developed a fluorescent switching based on bovine serum albumin stabilized gold nanoclusters (BSA-AuNCs) and kanamycin (Kana) aptamer to detect Kana. Red fluorescence of BSA-AuNCs was turn off when Kana aptamer was assembled on the surface of BSA-AuNCs. However, after adding Kana, the specific aptamer detached from the surface of the BSA-AuNCs and formed the complex of aptamer-kanamycin, then the red fluorescence of BSA-AuNCs was turn on. The fluorescence intensity of BSA-AuNCs can be mediated by the amount of Kana aptamer. A good linear response for Kana was obtained in the concentration range 0.04 nM to 7.0 nM. The assay was used to detect Kana in milk matrix, and the accuracy and recovery of the method were satisfied. It is worth noting that the aptamer mediated BSA-AuNCs fluorescent switching was simple and easy to fabricate, which can provide a novel assay for the detection of small molecules. [ABSTRACT FROM AUTHOR]