Multiscale Three-Dimensional Vertical Graphene-Encapsulated Nanoparticle Coatings for Antibacterial Applications against Multidrug-Resistant Bacteria.

Implant-associated infections caused by multidrug-resistant Staphylococcus aureus (S. aureus) remain a major clinical challenge, underscoring the urgent need for surface-engineered antibacterial strategies that extend beyond conventional antibiotic delivery. Here, we report a hierarchical antimicrobial coating that integrates chemical surface functionalization, nanoparticle (NP) assembly, vertical graphene (VG) growth, and antibiotic incorporation into a hybrid platform. The resulting three-dimensional composite coating (Si/APTES/NPs/VG) features a NP-mediated interfacial layer and vertically oriented graphene with a high drug-loading capacity, enabling localized, contact-mediated antibacterial activity. The Si/APTES/NPs/VG/vancomycin coating exhibited potent antibacterial efficacy, achieving a 10000-fold reduction in viable bacteria, achieving 99.99% antibacterial efficiency. Importantly, the coating also maintained favorable cytocompatibility, highlighting its potential for biomedical implant applications. Overall, this work establishes a versatile strategy for constructing carbon-based bioactive surfaces and provides a promising approach for preventing infections caused by drug-resistant S. aureus.