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Ratiometric Fluorescent Detection of Intracellular Singlet Oxygen by Semiconducting Polymer Dots
摘要： Singlet oxygen (1O2) plays important roles in many biological processes. However, it is very difficult to detect 1O2 in the intracellular environment owing to its relatively low concentration and short lifetime. Here, we developed a ratiometric probe based on semiconducting polymer dots (Pdots) that can sensitively detect 1O2 in live cells. An organic dye, singlet oxygen sensor green (SOSG), was doped in polyfluorene Pdots, and excitation energy was efficiently transferred from the polymer to the SOSG dye. Accordingly, the Pdots showed constant blue fluorescence as a reference, and increased green fluorescence upon singlet oxygen generation. The ratiometric response of Pdots was examined in the intracellular environment by in-situ 1O2 generation with a photosensitizer and light irradiation. Both spectroscopic measurements and confocal imaging were performed to monitor intracellular 1O2 generation during photodynamic therapy using the Pdot probe. Our results indicate that the SOSG-doped Pdots are promising for intracellular 1O2 detection.
关键词： Semiconducting polymer dots,Intracellular detection,Singlet oxygen,Photodynamic therapy,Ratiometric probe
更新于2025-09-11 14:15:04
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Extremely Photostable Electron-Deficient Phthalocyanines That Generate High Levels of Singlet Oxygen
摘要： A robust lead-mediated synthetic procedure for the generation of phthalocyanines substituted with electron-withdrawing groups has been developed. The free-base phthalocyanine and various metal complexes were prepared without discernible degradation of the peripheral electron-withdrawing substituents. Upon irradiation with red light, some of the thus obtained metal complexes generated high levels of singlet oxygen. Especially a palladium complex exhibited attractive photostability upon exposure to singlet oxygen as a bleaching agent. The photostability of such complexes that may manifest concomitantly to the generation of high levels of singlet oxygen was attributed to the presence of the electron-withdrawing groups, which results in energetically low-lying highest occupied molecular orbitals.
关键词： lead,phthalocyanine,singlet oxygen,electron-withdrawing group,photostability
更新于2025-09-10 09:29:36
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Synthesis, Structure, Photophysical Properties, and Photostability of Benzodipyrenes
摘要： We explored the syntheses, structure, photophysical properties, and photostability of benzodipyrenes (BDPs). BDPs were synthesized through an InCl3-AgNTf2 catalyzed, four-fold alkyne benzannulation reaction. The structures of BDP 4a and its corresponding endoperoxide product were unambiguously confirmed by X-ray crystallography. The BDPs reported here can also be recognized as peri- and cata-benzannulated pentacenes with a non-functionalized central ring. Unlike the previous reported pentacene-based polycyclic aromatic hydrocarbons, the absorbance of the BDPs was blue-shifted by ca. 40 nm relative to pentacene, even after extension of π–conjugation. The newly synthesized BDP products exhibit good relative stability with half-lives as high as 4612 min in THF.
关键词： pentacene,benzannulation,alkyne,singlet oxygen,photostability
更新于2025-09-10 09:29:36
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The Ability of Functionalized Fullerenes and Surface Modified TiO <sub/>2</sub> Nanoparticles to Photosensitize Peroxidation of Lipids in Selected Model Systems
摘要： 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.
关键词： Lipid peroxidation,Melanin,Fullerenes,Singlet oxygen,TiO2 nanoparticles,Free radicals,Photodynamic therapy
更新于2025-09-10 09:29:36
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Helicenic complexes of lanthanide: influence of f-element on the inter-system crossing efficiency and competition between luminescence and oxygen sensitization.
摘要： The coordination of a helicen functionalized bipyridine to various lanthanide complexes (Ln = Y, Eu, Yb, Gd) led to the formation of an isostructural series. The photophysical study indicated that non-emissive lanthanide act as heavy atoms strongly enhancing the singlet oxygen generation. We also demonstrated that sensitization of the f-f luminescence is in competition with singlet oxygen generation.
关键词： singlet oxygen generation,lanthanide,photodynamic therapy,luminescence,helicen
更新于2025-09-09 09:28:46
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Elucidating the mode of action for thiophene-based organic D-π-A sensitizers for use in photodynamic therapy
摘要： Photodynamic therapy (PDT) is a non-invasive, selective, and cost-effective cancer therapy. The development of readily accessible templates that allow rapid structural modification for further improvement of PDT remains important. We previously reported thiophene-based organic D-π-A sensitizers consisted of an electron-donating (D) moiety, a π-conjugated bridge (π) moiety, and an electron-accepting (A) moiety as valuable templates for a photosensitizer that can be used in PDT. Our preliminary structure-activity relationship study revealed that the structure of the A moiety significantly influences its phototoxicity. In this study, we evaluated the photoabsorptive, cellular uptake, and photo-oxidizing abilities of D-π-A sensitizers that contained different A moieties. The level of phototoxicity of the D-π-A sensitizers was rationalized by considering those three abilities. In addition, we observed the ability of amphiphilic sensitizers containing either a carboxylic acid or an amide in an A moiety to form aggregates that penetrate cells mainly via endocytosis.
关键词： Organic dye,Photodynamic therapy,Sensitizer,Singlet oxygen,Endocytosis
更新于2025-09-09 09:28:46
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A systematic investigation on the bactericidal transient species generated by photo-sensitization of natural organic matter (NOM) during solar and photo-Fenton disinfection of surface waters
摘要： In this work, the role of dissolved oxygen in the solar and the photo-Fenton-mediated E. coli inactivation process was put under scrutiny. The effect of transient species that were produced in the Nordic Reservoir (NR) NOM, SR Humic acid (SRHA), and SR Fulvic acid (SRFA) was studied in presence of various natural organic matter isolates (NOM), namely Suwannee River (SR) NOM, detail. The role of 1??2 in this reaction was systematically evaluated by modifying the O2 concentration (N2/O2 purging) and the matrix composition (10, 50, and 100% deuterium oxide (D2O) v/v). In the presence of NOM, 1??2 was generated and the enhancement of E. coli inactivation rate due to charge transfer from triplet state to molecular oxygen. The comparison between SR and NR NOM showed that for these compounds, triplet state of NOM (3NOM*), and 1??2 were the more favorable active species in E. coli inactivation, respectively. Also, the second order rate constants (????.???????? 2???? ) of E. coli with 3NOM*, and 1??2 were calculated by using the steady state approximation. The obtained results showed that the rate values of 1??2 related to NR NOM was ~ 5.6 times higher than SR NOM, while the rate values of 3NOM* for SR NOM was ~ 8.7 times higher than NR NOM. We also determined the effect of these organic matter isolates in the photo-Fenton process and its constituents (solar/Fe2+, solar/H2O2, and solar/Fe2+/H2O2). In presence of NOM, the photo-Fenton process inactivation rates increased which confirmed that the combined processes has additional pathways generated with disinfecting effect during solar exposure of bacteria.
关键词： solar disinfection (SODIS),singlet oxygen,triplet state,Advanced oxidation process (AOPs),E. coli
更新于2025-09-09 09:28:46
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Synthesis, photodynamic activities, and cytotoxicity of new water-soluble cationic gallium(III) and zinc(II) phthalocyanines
摘要： The cationic Ga(III) and Zn(II) phthalocyanines carrying N-methyl-pyridinium groups at eight peripheral β-positionshave been synthesized. These complexes are highly soluble in dimethyl sulfoxide (DMSO) and moderately soluble in water and phosphate buffered saline (PBS); both Ga(III)Cl and Zn(II) complexes have shown no aggregation in water up to 1.2×10-4 and 1.5×10-5 M, respectively. A higher water-solubility of Ga(III)Cl complex as compared to Zn(II) complex is ascribed to the presence of an axially coordinated chloride. The spectroscopic properties, photogeneration of singlet oxygen (1O2), and cytotoxicity of these complexes have been investigated. The absolute quantum yields (???absolute) for the photogeneration of singlet oxygen using Ga(III)Cl and Zn(II) complexes have been determined to be 4.4 and 5.3 %, respectively, in DMSO solution. The cytotoxicity and intracellular sites of localization of Ga(III)Cl and Zn(II) complexes have been evaluated in human HEp2 cells. Both complexes, localized intracellularly in multiple organelles, have shown no cytotoxicity in the dark. Upon exposure to a low light dose (1.5 J/cm2), however, Zn(II) complex has exhibited a high photocytotoxicity. The result suggests that Zn(II) complex can be considered as a potential photosensitizer for Photodynamic therapy (PDT).
关键词： PDT,Water-soluble,singlet oxygen,Phthelocyanine
更新于2025-09-09 09:28:46
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Confinement of Singlet Oxygen Generated from Ruthenium Complex-Based Oxygen Sensor in the Pores of Mesoporous Silica Nanoparticles
摘要： We synthesized mesoporous silica nanoparticles bearing ruthenium complexes in their pores (MSN-Ru) and characterized their photochemical properties. The ruthenium complexes that were immobilized in the pores showed oxygen-dependent phosphorescence, similar to the complexes that were not tethered to nanoparticles. Cellular imaging and in vivo experiments revealed that hypoxic cells and tissues could be visualized by monitoring the phosphorescence of MSN-Ru. Our most important finding was that the toxic effect of singlet oxygen (1O2), which was generated by excitation of the complexes, was effectively suppressed by the deactivation before leaking out from the pores. In addition, we observed a negligible toxic effect of the ruthenium complexes themselves due to the blockage of their direct interaction with intracellular biomolecules. Thus, MSN-Ru is a promising molecular probe of oxygen levels in living cells and tissues.
关键词： ruthenium complexes,singlet oxygen,in vivo experiments,cellular imaging,oxygen sensor,mesoporous silica nanoparticles
更新于2025-09-04 15:30:14
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Contribution à l’étude de la désinfection de l’eau par photosensibilisation avec des extraits de plantes
摘要： Some plants used in the traditional pharmacopoeia to treat microbial and parasitic infections are able to generate singlet oxygen. This is used to disinfect the water. The study of the disinfection of water by photosensitization with the flavonoid extracts of Aframomum alboviolaceum shows a complete inhibition of fecal coliforms present in the water after one hour of sunshine for the two isolated products by column chromatography of the roots of this plant. Regarding the water samples treated with these two products and kept in the dark, no inhibition was noted from the beginning to the end of the experiments. This suggests that these products are photosensitizers and that in the presence of the sun they undergo photoexcitation which would lead to the formation of singlet oxygen. The latter, once generated, destroys the fecal coliforms present in water.
关键词： Photosensitization,Flavonoids,Singlet oxygen,Aframomum alboviolaceum,Sunstroke time
更新于2025-09-04 15:30:14