Red blood cell lysis photosensitized by ketoprofen (KPF) was investigated. The photohemolysis was inhibited by butylated hydroxyanisole, reduced glutathione, superoxide dismutase and mannitol, and was unaffected by sodium azide; the presence of oxygen markedly enhanced the lysis. Photohemolysis was also observed under anaerobic conditions. Ketoprofen, irradiated in aqueous buffer solution at pH 7.4, underwent a decarboxylation process via intermediate radicals, leading to the compounds (3-benzoylphenyl)ethane, (3-benzoylphenyl)ethyl hydroperoxide, (3-benzoylphenyl)ethanol and (3-benzoylphenyl)ethanone under aerobic conditions and only to the compound (3-benzoylphenyl)ethane under anaerobic conditions. The four photoproducts showed lytic activity, particularly high for the alcohol and hydroperoxide. The overall results suggest for KPF-photosensitized hemolysis a molecular mechanism involving free radicals, superoxide anion and sensitizer photodegradation products.

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The formation of colloidal metallic copper and of nanometer films on quartz and silicon substrates by irradiation of bis(2,4-pentanedionato)copper(II) ethanol solutions with UV light was investigated. The 254-nm-light absorption in the bulk of the solution causes formation of stable colloidal copper through two consecutive steps that could be distinguishable at low light intensity. In the first step, the starting complex releases one ligand and forms of copper(I) species that quickly release the second ligand and evolve to copper(I) alkoxides. In the second step, these latter undergo reduction to colloidal copper by the released acetylacetone with an electronic transfer process. Acetone sensitizes reduction to metallic copper with radical pathways. Features of the process depend on the acetone concentration so that either nanoparticles of colloidal copper or fine powder can be fabricated from the solution. In the presence of quartz or silicon substrate, placed in the suitable apparatus, the light absorption at the substrate−solution interface induces the formation of pure thin metallic copper films with nanometer characteristics. The photodeposition involves almost a heterogeneous process. The photoreaction has been followed by UV−vis and 1H NMR spectroscopy while the copper(I) species have been detected by ESI-MS analysis and IR spectroscopy; copper powder and the films have been investigated by XRD, XPS, and SEM techniques. A mechanism of direct and acetone-sensitized formation of nanoparticles of copper is proposed, based on the role of the released ligand and on the photochemistry of the acetone.

Nanometer-sized copper metal can be formed by UV irradiation of ethanol bis(2,4-pentanedionate)copper(II) solutions: simple tuning of the irradiation conditions switches the process from homogeneous to heterogeneous nucleation, and promotes the formation of either colloidal powders or nanostructured films.

Ultraviolet-A irradiation of a suprofen (2-[4-2(2-thenoyl) phenyl]propionic acid) (SPF) buffered solution (pH 7.4) in the presence of supercoiled pBR322 DNA leads to single strand breaks with the formation of an open circular form and subsequent linearization of the plasmid. On the basis of agarose gel electrophoresis data of samples irradiated in an air-saturated solution or in an oxygen-modified atmosphere, and the effects of sodium azide, D20, mannitol, copper(II), superoxide dismutase, 2-H-propanol, deferoxamine and surfactants, we suggest a photosensitization mechanism involving singlet oxygen and free radicals. The higher rate of photocleavage in nitrogen compared to that in an air-saturated solution and the results obtained from oxygen consumption measurements support the hypothesis that both the type I and type II photosensitization mechanisms are operative and that oxygen quenches the excited state of the irradiated drug. The photosensitization model applied was in agreement with that previously applied to cell membrane SPF photoinduced damage. Interaction of the drug with DNA, studied through circular dichroism and fluorescence anisotropy, probably occurs through a surface binding mode. The experimental techniques used for assessing the photodamaging activity of this drug may be useful for screening of phototoxic compounds in the environment and for determining the active species involved.