Surface engineering of magnetic peroxidase mimic using bacteriophage for high-sensitivity/specificity colorimetric determination of Staphylococcus aureus in food.

Herein, we proposed surface engineering of magnetic peroxidase mimic using bacteriophage by electrostatic interaction to prepare bacteriophage SapYZU15 modified FeO (SapYZU15@FeO) for colorimetric determination of S. aureus in food. SapYZU15@FeO exhibits peroxidase-like activity, catalyzing 3,3',5,5'-tetramethylbenzidine (TMB) chromogenic reaction. After introducing S. aureus, peroxidase-like activity of SapYZU15@FeO was specifically inhibited, resulting in deceleration of TMB chromogenic reaction. This phenomenon benefits from the presence of unique tail protein gene in the bacteriophage SapYZU15 genome, leading to a specific biological interaction between S. aureus and SapYZU15. On basis of this principle, SapYZU15@FeO can be employed for colorimetric determination of S. aureus with a limiting detection (LOD), calculated as low as 1.2 × 10 CFU mL. With this proposed method, colorimetric detection of S. aureus in food was successfully achieved. This portends that surface engineering of nanozymes using bacteriophage has great potential in the field of colorimetric detection of pathogenic bacterium in food.