One-Arrow-Three Hawks: Antibiotic-Derived Nanozybiotics with Retained Antibacterial Activity and Dual Peroxidase-/Catalase-like Nanozyme for Potential ROS Modulation.

Antibiotic resistance and oxidative stress-associated infections demand next-generation antimicrobial platforms that move beyond conventional drug mechanisms. Here, we present a nanozybiotic system comprising antibiotic-derived multienzyme-mimic carbon quantum dots co-doped with Cu/Ru (Cu/Ru-Moxi CDs). Engineered through a one-step hydrothermal approach, this platform incorporates a "One-Arrow-Three Hawks" strategy: (i) the retention of intrinsic antibacterial activity from Moxifloxacin, (ii) the emergence of dual peroxidase- (POD)- and catalase (CAT)-like nanozyme activities, and (iii) a pH-dependent catalytic response for potential reactive oxygen species (ROS) modulation. Cu/Ru-Moxi CDs exhibit strong POD- and CAT-like catalytic activity toward H2O2 (Km-TMB = 45.3 µM, Km-H2O2 = 555.3 µM). The nanozyme behavior further confers free-radical scavenging capability and pH-dependent POD- and CAT-like activity toward potential ROS modulation. The biological studies show retained antimicrobial activity against Gram-positive and Gram-negative bacteria, including multidrug-resistant MRSA, and even Mycobacterium tuberculosis (M. tuberculosis) (H37Rv/H37Ra). The Cu/Ru-Moxi CDs show enhanced biofilm inhibition against MRSA as compared to tested antibiotics. Moreover, the Cu/Ru-Moxi CDs show good cytocompatibility with CC50 > 100 µg/mL. The integration of precursor-derived antibiotic functionality with bimetallic catalytic centers, provides bactericidal action, dual nanozyme activity, and pH-dependent catalytic response, making Cu/Ru-Moxi CDs a promising multifunctional nanozybiotic platform.