基于竞争效应驱动类漆酶活性纳米酶比色/荧光双模检测β-内酰胺类抗生素残留OA

β-Lactam antibiotics(BLs)are widely used for preventing and treating bacterial infections in poultry and livestock.However,their abuse and irrational use have led to excessive residues in animal-derived foods,posing a significant threat to consumer health and safety.Thus,there is an urgent need to develop rapid,sensitive,and reliable on-site detection methods for BLs.In this study,a copper metal-organic framework(Cu-MOF)with both laccase-like activity and fluorescent properties was synthesized via a solvothermal method.Cu-MOF could catalyze the oxidation of colorless o-phenylenediamine(OPD)to yellow 2,3-diaminophenazine(DAP)using O2 as the oxidant,resulting in a characteristic absorption peak at 418 nm.Under excitation at 365 nm,DAP emitted yellow fluorescence at 550 nm,which could quench the blue fluorescence of Cu-MOF at 425 nm through the inner-filter effect(IFE).BLs could competitively inhibit the oxidation of OPD to DAP,leading to a decrease in the absorbance of DAP at 418 nm and the intensity of its yellow fluorescence at 550 nm,accompanied by the recovery of the blue fluorescence of Cu-MOF at 425 nm.This dual response generated both colorimetric signals and ratiometric fluorescent signals(F425/F550).Based on the colorimetric/ratiometric fluorescent dual-mode response of the sensing system to BLs,a portable on-site analytical method for BL concentration detection was established by combining the image acquisition function of a smartphone with the RGB information extraction capability of ImageJ software.The linear response ranges of the colorimetric and fluorescent modes were 0.56–30 μmol/L and 0.40–5 μmol/L,with limits of detection(LOD=3σ/k)of 0.19 μmol/L and 0.13 μmol/L,respectively.This method was successfully applied to detection of BLs residues in pork and beef,providing a novel strategy for rapid on-site screening and quantitative analysis of antibiotic residues in foods.