Interfacial engineering of silver quantum dots for antibacterial applications: From surface chemistry to translational design

Silver quantum dots (Ag QDs) are emerging antibacterial nanomaterials whose activity depends not only on silver content or nanoscale size but also on structure–surface interactions. This review analyzes Ag QDs as structure–surface–function systems, highlighting the roles of quantum confinement, surface coordination, ligand/capping chemistry, colloidal stability, and synthesis-dependent variability. Evidence from green and biosynthesized Ag QDs, polymer-stabilized systems, silica/PAAc matrices, photoactive hybrids, Schiff-base-functionalized Ag₂S QDs, and targeted antimycobacterial platforms is critically discussed. Antibacterial performance is evaluated through biointerface interactions, oxidative stress, membrane disruption, intracellular damage, photo-assisted disinfection, ligand-controlled activity, and matrix-mediated localization. Key challenges, including inconsistent Ag QD definitions, limited mechanistic attribution, heterogeneous assays, toxicity concerns, reproducibility, scalability, and controlled silver accessibility, are examined. Overall, this review emphasizes that future Ag QD translation requires surface-engineered, mechanism-guided, and safety-oriented design strategies rather than empirical optimization of antibacterial potency alone.