Bioinspired antibacterial silver nanocomposites derived from fish scale architectures: from natural surface characteristics to functional antimicrobial coatings

This study explores the untapped potential of fish scales (FS) as bioinspired platforms for antibacterial applications through a dual approach: (1) systematic characterization of natural scale architectures and (2) development of functional silver nanocomposites (FS-AgNCs). Comprehensive analysis revealed zonal differentiation in grass carp scales, with outer surfaces exhibiting ridge patterns (19–54 μm width) and protrusions, while inner surfaces remained smooth. The covered area (25.78% of surface) showed higher organic content (37.5%) than the exposed zone (30% organic). Leveraging these natural features as nucleation sites, we developed FS-AgNCs via in situ reduction, forming uniformly distributed Ag nanoparticles (248 ± 3 nm and 575 ± 9 nm populations). The nanocomposites demonstrated potent antibacterial activity, achieving 10.4 ± 0.2 mm inhibition zones and 97% killing efficiency against pathogenic bacteria—significantly outperforming bare scales ( P  < 0.05). In vivo testing confirmed both biosafety and delayed mortality in Aeromonas hydrophila -challenged fish, with 100% survival maintained over 4 days in treated groups compared to 62.5% mortality within 24 h in controls. This work establishes a sustainable paradigm for developing biocompatible antimicrobial materials by integrating natural biomimetic structures with nanotechnology, offering promising applications in aquaculture and medical coatings.