Construction of a smartphone-assisted colorimetric nanosensor with multi-antibiotic response based on silver–ceria nanocomposites mimicking peroxidase activity

catalytically oxidizes colorless 3,3',5,5'-tetramethylbenzidine (TMB) into its blue oxide (oxTMB). However, the chromogenic reaction is inhibited in the presence of antibiotics, and the inhibition effect relies on the concentration of antibiotics. The colorimetric sensor can respond to three common antibiotics, namely, tetracyclines, aminoglycosides, and penicillin. The highly sensitive detection of tetracycline (TC), kanamycin A (Kana), and amoxicillin (AMX) has been proven. In addition, smartphone-assisted digital image analysis is utilized for quantitative detection, enabling rapid on-site detection. The developed sensor is further successfully applied to quantify antibiotic residues in actual samples such as drinking mineral water, tap water, and milk, with gratifying results achieved. This study furnishes a novel alternative for the rapid on-site screening of antibiotic residues and delivers valuable insights into the application of nanozymes in food safety monitoring.