A simple tag-free fluorometric aptasensing assay for sensitive detection of kanamycin

A novel label-free and enzyme-free fluorescence aptasensing assay that uses Sybr Green I (SGI) as the signal indicator for the kanamycin determination was designed. An aptamer-complementary strand (Apt/CP) conjugate was formed, which provided the intercalation sites for SGI and, therefore, a considerable fluorescent signal. The introduction of the target led to the separation of Apt from CP due to the high affinity of Apt toward kanamycin. Hence, the suitable intercalation gaps reduced, which resulted in a decrease in the generated fluorescent signal. Under optimized conditions, a broad linear concentration range from 0.05 μM to 20 μM and a limit of detection of 11.76 nM were obtained, confirming the ability of the fabricated aptasensor for sensitive and specific kanamycin detection in real samples such as milk and human serum. The aptasensing method has the potential to be extensively employed in the food industry and veterinary science due to its simplicity, sensitivity, user-friendly, and capability of on-site detection of kanamycin.