Enhanced Nanozymatic Activity on Rough Surfaces for H₂O₂ and Tetracycline Detection

The needless use of tetracyclines (TCs) in foodstuffs is a huge health concern in low- and middle-income and Arab countries. Herein, a sensitive and faster monitoring system for H₂O₂ and TCs is proposed, utilizing the large surface-to-volume ratio of a non-spherical gold nanoparticle/black phosphorus nanocomposite (BP-nsAu NPs) for the first time. BP-nsAu NPs were synthesized through a single-step method that presented nanozymatic activity through 3,3',5,5'-Tetramethylbenzidine (TMB) oxidation while H₂O₂ was present and obeyed the Michaelis-Menten equation. The nanozymatic activity of the BP-nsAu NPs was enhanced 12-fold and their detection time was decreased 83-fold compared to conventional nanozymatic reactions. The proposed method enabled us to quantify H₂O₂ with a limit of detection (LOD) value of 60 nM. Moreover, target-specific aptamer-conjugated BP-nsAu NPs helped us detect TCs with an LOD value of 90 nM. The present strategy provides a proficient route for low-level TC monitoring in real samples.