A competitive colorimetric aptasensor for simple and sensitive detection of kanamycin based on terminal deoxynucleotidyl transferase-mediated signal amplification strategy

•Integration of TdTase-mediated signal amplification technique and colorimetry.•MBs serve for rapid magnetic separation of the captured target from sample matrix.•Desirable detection sensitivity (9 pM) and specificity for kanamycin standard.•Simple, highly sensitive and suitable for on-site food safety screening.