The Ability of Functionalized Fullerenes and Surface‐Modified TiO₂ Nanoparticles to Photosensitize Peroxidation of Lipids in Selected Model Systems

Abstract

Photochemical properties of a new class of inorganic nanoparticles, namely a cationic C60 fullerene substituted with three quaternary pyrrolidinium groups (BB6) and a surface‐modified nanocrystalline TiO2 with bromopyrogallol red (Brp@TiO2) were examined for their effectiveness in photogenerating singlet oxygen and free radicals. In particular, their ability to photosensitize peroxidation of unsaturated lipids was analyzed in POPC:cholesterol liposomes and B16 mouse melanoma cells employing a range of spectroscopic and analytical methods. Because melanoma cells typically are pigmented, we examined the effect of melanin on the photosensitized peroxidation of lipids in liposomes and B16 melanoma cells, mediated by BB6 and Brp@TiO2 nanoparticles. The obtained results suggest that peroxidation of unsaturated lipids, photosensitized by BB6 occurs mainly, although not exclusively, via Type II mechanism involving singlet oxygen. On the other hand, if surface‐modified TiO2 is used as a photosensitizer, Type I mechanism of lipid peroxidation dominates, as indicated by the predominant formation of the free radical‐dependent cholesterol oxidation products. The protective effect of melanin was particularly evident when BB6 was used as a photosensitizer, suggesting that melanin could efficiently interfere with Type II processes.

Melanoma and Nanotechnology-Based Treatment

“…Inorganic nanoparticles, including silica nanoparticles, gold nanoparticles, copper nanoparticles, and nanotubes, have good biocompatibility and enable simultaneous imaging and drug delivery ( 47 , 48 ). However, these nanoparticles may not permit specific targeting to the affected region and generally need to be coupled with other targeting ligands.…”

“…Kozinska et al. applied functionalized fullerenes and surface-modified TiO 2 as a photosensitizer for melanoma treatment and demonstrated that novel inorganic nanoparticles can achieve photodynamic killing of melanoma cells; this novel inorganic TiO 2 nanoparticle complex was shown to have a longer retention time in vivo and to be nontoxic and stable under conditions without light irradiation ( 47 ). Ferreira et al.…”

Fine Particulate Matter-Induced Oxidative Stress Mediated by UVA-Visible Light Leads to Keratinocyte Damage

“…In the presence of light and hydrogen peroxide, redox-active metal ions such as iron and copper can generate hydroxyl radicals and possibly other reactive oxygen species (ROS) [ 6 ]. Moreover, certain semiconductors such as titanium dioxide (TiO 2 ) and zinc oxide (ZnO) irradiated with visible or near-UV light can produce oxygen radicals and singlet oxygen [ 6 , 7 , 8 ]. Organic compounds including dyes, porphyrins, and aromatic hydrocarbons (e.g., benzo[a]pyrene) present in airborne pollution [ 9 , 10 , 11 , 12 , 13 ] can exhibit substantial photosensitizing ability to generate singlet oxygen.…”

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

“…Nanomaterials possess their unique physical and chemical properties as a result of quantum effect, largely influenced by the size and geometry of the material [26,27]. Another beneficial aspect of nanoscale surface topography of the materials is high surface area and its interactions with biologically important molecules present in bacteria cells (e.g., proteins, DNA, or lipid membranes) [28][29][30]. Nano-sized agents are able to enhance the internalization processes, locally change the microenvironment near the bacteria, increase solubility, and generate ROS responsible for bacterial cells damage [31,32].…”