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

Abstract

The improper overuse of veterinary antibiotics in agricultural breeding practices has resulted in their accumulation in food commodities and triggered pervasive concerns regarding food safety. The rapid detection of antibiotic residues is a crucial measure in ensuring food safety. In this study, a nanohybrid of silver and ceria (AgNP@CeO2) exhibiting peroxidase-like (POD-like) activity is synthesized and used to construct a colorimetric sensor that can respond to multiple antibiotics, achieving rapid and efficient screening of antibiotic contamination. Nanoceria exhibiting excellent recognition and adsorption capabilities toward various antibiotics is chosen as the recognition moiety of the sensor, and additionally, the incorporation of AgNPs can enhance the POD-like activity of ceria, thus achieving highly sensitive detection performance.The colorimetric sensing of antibiotics is based on the fact that the AgNP@CeO2 catalytically oxidize 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 including tetracyclines, aminoglycosides, and penicillins. The highly sensitive detection of tetracycline (TC), kanamycin A (Kana), and amoxicillin (AMX) are proved. In addition, smartphone-assisted digital image analysis is utilized to quantitative detection, enabling on-site rapid detection. The developed sensor is further applied successfully 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.