Silver-Loaded Titania-Based Metal-Organic Frameworks as a Platform for Silver Ion Release for Antibacterial Applications

Abstract

Conventional Ag-decorated TiO2 coatings suffer from low adsorption capacity and burst release kinetics, limiting long-term antibacterial efficacy and risking cytotoxicity. An entirely different payload release approach can be based on metal-organic frameworks (MOFs), which offer tunable porosity, high surface area, and internal diffusion channels. Here, we report a thermally stabilized Ti-based MOF [NH2-MIL-125(Ti)] functionalized with Ag+ via reactive deposition, enabling high Ag loading (similar to 14.7 wt %) and sustained release. Annealing at 250 degrees C enhances aqueous stability, allowing diffusion-governed Ag+ delivery over >48 h, with 77% of the Ag still present in the MOF after a 24 h release. The system exhibits dose-dependent antibacterial activity in powders and comparable efficacy in coatings, with a more gradual release profile. This scalable platform is promising for long-acting coatings, wound interfaces, and implantable materials.