Development of Cu-doped CeO2 nanospheres mimic nanozyme-based immunoassay for the specific screening of Bacillus cereus.

Due to the highly similar genetic background, it is difficult to distinguish Bacillus cereus (B. cereus) with other members of B. cereus group. Herein, an antibody-based colorimetric immunoassay using Cu-doped CeO₂ nanospheres as peroxidase mimics was developed for the detection of B. cereus in food. First, monoclonal antibodies (mAbs) and polyclonal antibody (pAb) with good specificity to B. cereus were prepared and characterized. Second, the regular-shaped hollow Cu/CeO₂ nanospheres with highly catalytic activity and biocompatibility were synthesized as mimic nanozymes to capture secondary antibody. Finally, a sandwich colorimetric immunoassay for the specific and sensitive detection of B. cereus was developed, showing linear detection range from 3.2 × 10² to 1 × 10⁵ CFU/mL and a limit detection of 1.7 × 10² CFU/mL. The developed immunoassay holds great potential as an effective tool for detecting B. cereus in food poisoning. [ABSTRACT FROM AUTHOR]