Dual-mode colorimetric and fluorescent detection of Staphylococcus aureus using a bacteriophage-modified nanozyme with tetra-(4-aminophenyl) ethylene as a dual-functional substrate.

Herein, a bacteriophage-modified nanozyme sensing platform was developed for dual-mode detection of Staphylococcus aureus in food samples. A peroxidase-like Fe/Ce metal-organic framework nanozyme was functionalized with bacteriophage SAYZU01 to obtain SAYZU01@Fe/Ce MOF, enabling specific recognition and capture of S. aureus. Tetra-(4-aminophenyl) ethylene (TPE-4A), an aggregation-induced emission-active molecule, was introduced as a dual-functional substrate to generate both colorimetric and fluorescent signals after catalytic oxidation. Compared with conventional TMB, TPE-4A provides complementary colorimetric and fluorescent readouts, allowing cross-checking of the sensing response. The captured bacteria inhibited the catalytic activity of SAYZU01@Fe/Ce MOF, resulting in concentration-dependent signal changes. Under optimized conditions, the platform achieved low detection limits of 1.48 × 101 CFU mL-1 for colorimetry and 1.27 × 101 CFU mL-1 for fluorometry, with a linear range of 2.43 × 101-2.43 × 107 CFU mL-1. This strategy provides a dual-mode approach for rapid pathogen detection in food safety monitoring.