Antibacterial Activity of ZnSe, ZnSe-TiO 2 and TiO 2 Particles Tailored by Lysozyme Loading and Visible Light Irradiation.

ZnSe, ZnSe-TiO 2 microspheres and nanostructured TiO 2 obtained by hydrothermal and sol-gel methods were tested against Staphylococcus aureus ATCC 25923 and Micrococcus lysodeikticus ATCC 4698 before and after lysozyme (Lys) loading. Morphological characterization of inorganic matrices and hybrid organic-inorganic complexes were performed by microscopy techniques (SEM, AFM and Dark Field Hyperspectral Microscopy). Light absorption properties of ZnSe, ZnSe-TiO 2 and TiO 2 powders were assessed by UV-visible spectroscopy and their ability to generate reactive oxygen species (•OH and O 2 •- ) under visible light irradiation was investigated. Antibacterial activity of ZnSe, ZnSe-TiO 2 , TiO 2 , Lys/ZnSe, Lys/ZnSe-TiO 2 and Lys/TiO 2 samples under exposure to visible light irradiation (λ > 420 nm) was tested against Staphylococcus aureus and Micrococcus lysodeikticus and correlated with ROS photogeneration.