Preparation of Cu-Zn oxide-loaded calcium carbonate composites and their long-lasting and efficient antimicrobial properties

Despite the continuous exploration and development of new antibiotics, the emergence of super-resistant bacteria has led to a gradual loss of effectiveness in some antibiotics. Developing new methods and applying antimicrobial materials can effectively reduce antibiotic usage, thereby slowing down the emergence of bacterial resistance. Herein, we present a novel micro-nano composite antimicrobial material synthesized through a one-pot method. This innovative system integrates ZnO, Cu2O, and CuCO3 onto CaCO3 carriers, demonstrating dual advantages of structural simplicity and functional synergy. The composite exhibits exceptional antimicrobial performance with minimum bactericidal concentrations of 15.625 µg/mL against Gram-negative bacteria and 7.8125 µg/mL against Gram-positive bacteria, while maintaining favorable biosafety. Mechanistic studies reveal a dual bactericidal action: (1) physical disruption of bacterial membranes through permeability alteration and structural damage, leading to critical cellular component leakage (e.g., DNA); (2) intracellular reactive oxygen species (ROS) overproduction triggering oxidative stress. Characterization by thermogravimetric analysis confirms its thermal stability and suitability for polymer processing. The cost-effective synthesis protocol and scalable production potential position this copper-zinc micro-nano composite as a promising candidate for advanced antimicrobial plastics engineering, addressing both efficacy and industrial feasibility requirements.