Synergistic Antibacterial Behavior of Carbon Dots via Both Contact-Dependent and -Independent Mechanisms

Antibiotic-resistant infections remain a major barrier to wound care, motivating antimicrobial biomaterials that are effective and locally activatable. Here, we report infection-responsive iron-doped carbon dots (FeCDs) synthesized via a one-pot hydrothermal route using biocompatible iron(II) gluconate. FeCDs eradicate bacteria through synergistic dual pathways: (i) a contact-independent mechanism in which iron doping confers peroxidase-like activity to catalyze reactive oxygen species (ROS) generation in H2O2-rich infection microenvironments, amplifying localized oxidative stress; and (ii) a contact-dependent mechanism where FeCDs electrostatically bind to bacteria and drive material-bacteria interfacial electron transfer, disrupting respiratory chains and energy production. Combined experiments and molecular dynamics simulations substantiate this synergistic coupling between catalytic and bioelectronic kinetics. Consequently, FeCDs exhibit broad-spectrum antibacterial ability with a high bactericidal rate (98.91%), and significantly accelerate infected wound healing with excellent biosafety. This work advances scalable carbon-based nanozymes, and highlights respiratory electron disruption as a powerful and complementary modality for anti-infective therapy.