Controlled Incorporation of Silver Nanoparticles into a Formate-Free MOF-808 Matrix: Toward a Robust Hybrid Antibacterial Material

Metal–organic frameworks (MOFs) are a class of porous materials with high surface areas, tunable pore structures, and chemical modularity, which enable a wide range of applications including catalysis, drug delivery, and sensing. The incorporation of metal nanoparticles into MOFs further expands their functionality by introducing additional reactive sites. Among these, silver nanoparticles (AgNPs) are of particular interest due to their well-documented antimicrobial, catalytic, and sensing properties. Herein, we report a strategy for encapsulating AgNPs within a modified MOF-808 (Zr) by removing formate ions and using a particle-free silver ink. We demonstrate that the formate removal is key to preventing premature reduction of AgNPs on the surface of MOF-808-FR (formate removed). Structural and morphological characterization confirms that Ag@MOF-808-FR remains intact after silver encapsulation, with AgNPs distributed throughout the framework. The material is stable in air for more than 90 days and stable in water for more than 1 week. As a proof-of-concept application, the antibacterial performance of Ag@MOF-808-FR was evaluated against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus, both in the presence and absence of hydrogen peroxide. The minimum inhibitory concentration (MIC) was determined to be 31.3 μg/mL for E. coli and 62.5 μg/mL for S. aureus. Minimum bactericidal concentration (MBC) was determined to be 125 μg/mL for E. coli and 62.5 μg/mL for S. aureus.