Hierarchical Quaternized Cuprous Oxide: A Single-Component Hybrid for Synergistic Antibacterial Surfaces and...

The fabrication of synergistic antimicrobial surfaces traditionally relies on complex, multi-component formulations that are often plagued by inherent compatibility and stability challenges. Herein, we report a "single-component" hybrid agent, quaternized cuprous oxide (Cu₂O@QPEI), synthesized via a polyethyleneimine-mediated hydrothermal assembly followed by N-alkylation. The resulting material features hierarchical "raspberry-like" microspheres comprising a polycationic QPEI shell chemically anchored to a Cu₂O core. Exhibiting intrinsic synergy, Cu₂O@QPEI achieves complete S. aureus (1 × 10⁶ CFU mL^-1) eradication within 6 h at a low minimum lethal concentration (MLC) of 5 μg mL^-1, significantly outperforming single-mode controls. The mechanism involves a "Breach-and-Payload" strategy, where the shell disrupts the bacterial membrane to facilitate rapid copper ion ingress. When incorporated into a topical hydrogel (5 μg g^-1), the hybrid significantly accelerated wound healing and reduced infection in a murine model. This work presents a "single-component agent" strategy to overcome traditional formulation challenges, offering a promising platform for developing next-generation synergistic antimicrobial materials for healthcare and industrial applications.