Eco-friendly synthesis of Tieguanyin tea-derived carbon dots for enhanced antibacterial applications

Antibacterial carbon dots (CDs) were synthesized from Tieguanyin tea to expand the functional applications of tea resources. The morphological, structural, and chemical properties of the CDs were systematically characterized by TEM, FT-IR, and XPS. These analyses confirmed that the CDs possess a well-defined graphite-like lattice and surface functional groups essential for interacting with bacterial cells. Notably, the tea-derived CDs exhibited potent antibacterial activity against clinically relevant drug-resistant pathogens, effectively overcoming existing resistance mechanisms. They showed strong inhibitory effects against S. aureus (MIC = 1.00 mg/mL) and E. coli (MIC = 1.20 mg/mL). The antimicrobial mechanism is attributed to the generation of reactive oxygen species (ROS) under illumination and electrostatic disruption of bacterial membranes driven by the cationic surface charge of the CDs. This study demonstrates the potential of tea as a promising platform for designing sustainable antibacterial nanomaterials, offering new insights into the integrated valorization of biomass resources and the mitigation of antibiotic resistance.