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Highly-active, surface-modified anatase TiO₂ nanoparticles were successfully synthesized and characterized. The morphological and optical properties of the obtained (metallo)porphyrin@qTiO₂ materials were evaluated using absorption and fluorescence spectroscopy, scanning electron microscopy (SEM) imaging, and dynamic light scattering (DLS). These hybrid nanoparticles efficiently generated reactive oxygen species (ROS) under blue-light irradiation (420 &#177; 20 nm) and possessed a unimodal size distribution of 20&#8722;70 nm in diameter. The antimicrobial performance of the synthetized agents was examined against Gram-negative and Gram-positive bacteria. After a short-term incubation of microorganisms with nanomaterials (at 1 g/L) and irradiation with blue-light at a dose of 10 J/cm², 2&#8722;3 logs of <i>Escherichia coli</i>, and 3&#8722;4 logs of <i>Staphylococcus aureus</i> were inactivated. A further decrease in bacteria viability was observed after potentiation photodynamic inactivation (PDI), either by H₂O₂ or KI, resulting in complete microorganism eradication even when using low material concentration (from 0.1 g/L). SEM analysis of bacteria morphology after each mode of PDI suggested different mechanisms of cellular disruption depending on the type of generated oxygen and/or iodide species. These data suggest that TiO₂-based materials modified with sulfonated porphyrins are efficient photocatalysts that could be successfully used in biomedical strategies, most notably, photodynamic inactivation of microorganisms.