Metal Nanoparticle-Reinforced Hydrogels Applied in the Inhibition of Clinical Pathogens: Structural Features, Mechanisms, and Biomedical Prospects

The increasing prevalence of antimicrobial resistance (AMR) has promoted the development of advanced biomaterials capable of overcoming the limitations of conventional antibiotics. In this context, metal nanoparticle hybrid hydrogels (MNHHs) have emerged as multifunctional platforms that integrate the high water-retention capacity and biocompatibility of hydrogels with the antimicrobial properties of metallic nanoparticles (MNPs). This review critically analyzes recent advances in the design, physicochemical properties, antimicrobial mechanisms, and biomedical applications of these systems. Current evidence demonstrates that MNHHs can achieve antimicrobial efficiencies above 98–99%, with minimum inhibitory concentrations as low as 0.78 µg mL−1 and inhibition zones of up to 25 mm against clinically relevant pathogens. Furthermore, the incorporation of MNPs significantly improves the mechanical properties of hydrogels and enables controlled and sustained metal ion release for periods of up to 14 days. Despite these promising results, important challenges remain regarding cytotoxicity, release control, the lack of experimental standardization, and the limited understanding of long-term biological effects. Overall, MNHHs represent a promising strategy for infection control, regenerative medicine, and controlled drug delivery; however, their clinical translation still requires the development of reproducible, safe, scalable, and highly biocompatible systems.