Surface topography and nanostructural modifications for the prevention of bacterial infections

Implant-associated infections represent severe complications in orthopaedics and trauma surgery, largely driven by early bacterial adhesion and subsequent biofilm formation on device surfaces. The increasing incidence of multidrug-resistant pathogens further complicates management and underscores the urgent need for preventive, antibiotic-free strategies. Surface functionalization of implantable metals has emerged as a key approach to inhibit bacterial colonization at the implant-tissue interface while minimizing systemic toxicity and selective pressure for resistance. This review provides a comprehensive and clinically oriented overview of two major surface-based strategies: micro/nano-scale surface patterning (non-releasing approaches) and nanostructured antibacterial metallic coatings (releasing or contact-killing systems). Surface patterning modifies topography, wettability, and surface charge to reduce bacterial adhesion or induce mechanical disruption of bacterial membranes. Although highly promising in vitro and not reliant on the release of antimicrobial agents, hence not inserting compounds with potential toxicity, current evidence indicates that patterned surfaces alone often provide limited and transient protection in vivo, where protein adsorption and complex microbial communities may mask topographical effects. In contrast, nanostructured antibacterial metallic coatings offer broad-spectrum antibacterial and antibiofilm activity through ion release and/or contact-mediated mechanisms. Advances in plasma-assisted deposition technologies, including magnetron sputtering, pulsed laser deposition, and ionized jet deposition, enable precise control over coating thickness, morphology, and ion-release kinetics, thereby enhancing antibacterial efficacy while preserving biocompatibility and osteogenic potential. Recent in vivo data support the durability and safety of thin nanostructured coatings, highlighting their translational potential. Although not-yet clinically available, due to challenges in clinical translation of biomedical devices, these strategies can build a new generation of antibacterial device, with efficacy targeted to the microbial community and to tackling biofilm. Comparative observations suggest that while surface patterning represents a valuable complementary strategy, nanostructured metallic thin films currently provide more robust and clinically relevant antimicrobial performance. Future research should prioritize standardized antibiofilm testing models, validation in complex in vivo settings, combination strategies integrating patterning and coatings, and the rational tuning of multi-metal systems to address heterogeneous microbial communities.