Surface Modification of Nanocrystalline TiO2 Materials with Sulfonated Porphyrins for Visible Light Antimicrobial Therapy

Abstract

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 ± 20 nm) and possessed a unimodal size distribution of 20–70 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, 2–3 logs of Escherichia coli, and 3–4 logs of Staphylococcus aureus 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.

Photodynamic Inactivation of Bacteria with Porphyrin Derivatives: Effect of Charge, Lipophilicity, ROS Generation, and Cellular Uptake on Their Biological Activity In Vitro

“…After this incubation, cells were washed with PBS (without Ca 2+ and Mg 2+ ) and then incubated with APF (25 µM) prepared in PBS for the next 2 h. After this time, cells were washed twice with PBS and irradiated with 10 J/cm 2 blue light (LED diode, 420 ± 20 nm, Instytut Fotonowy, Kraków, Poland). studies [ 85 ]. After irradiation, cells were collected by centrifugation and resuspended in 1 mL of PBS examined using BD Accuri™ C6 flow cytometer.…”

Photodynamic Antimicrobial Chemotherapy: Advancements in Porphyrin-Based Photosensitize Development

“…Using various techniques that involve either complexation or covalent conjugations, various biomaterials have been employed in the modification of the physico-chemical and pharmacological properties of the attached porphyrin. For example, metals such as titanium dioxide (TiO 2 ) have been complexed with meso-tetrakis (p-sulfonatophenyl) porphyrin, and the resulting complexes showed improved photostability, fluorescence, and self-assembly into nanoparticles ( Sułek et al, 2019 ). Another approach has involved the conjugation with amino acids, which added hydrophilicity and overall positive charge of the system.…”

Latest trends on photodynamic disinfection of Gram-negative bacteria: photosensitizer’s structure and delivery systems

“…One can also cite the work of Sułek et al, who investigated visible-lightactivated TiO 2 -based materials, modified by tetra sulfonated porphyrin derivatives (161-164, Fig. 18), and formulated as transparent colloidal solutions [118,119] . However, although only 1-2-log decrease in survival of E. coli was monitored after 20 J/cm 2 of blue or green light (420 nm or 530 nm), the authors improved the efficiency of their systems with KI potentiation, leading to a reduction of up to five logs under visible light irradiation.…”