In Parkinson's disease (PD), dopamine neurons containing neuromelanin selectively degenerate. Neuromelanin binds iron and accumulates in aging. Iron reactive form during aging, PD, is involved neurodegeneration. It not clear how the interaction of can be protective or toxic by modulating redox processes. Here, we investigated from human substantia nigra with presence ascorbic acid, dopamine, hydrogen peroxide. We observed that blocks hydroxyl radical production Fenton's reaction, a...

Light-induced radical generation is the hallmark of fundamental processes and many applications including photosynthesis photodynamic therapy (PDT). In this manuscript, we present two novel observations made upon monitoring light-induced reactive oxygen species (ROS) in aqueous solutions by WST11, a water-soluble derivative photosynthetic pigment Bacteriochlorophyll (Bchl). Using host complementary experimental techniques time-resolved spectroscopy at subpicosecond to millisecond range, ESR...

It is known that noncationic porphyrins such as Photofrin (PF) are effective in mediating antimicrobial photodynamic inactivation (aPDI) of Gram-positive bacteria or fungi. However, the aPDI activity PF against Gram-negative accepted to be extremely low. Here we report nontoxic inorganic salt potassium iodide (KI) at a concentration 100 mM when added microbial cells (108/mL) + (10 μM hematoporphyrin equivalent) 415 nm light J/cm2) can eradicate (>6 log killing) five different species...

Rose bengal (RB) is a halogenated xanthene dye that has been used to mediate antimicrobial photodynamic inactivation for several years. While RB highly active against Gram-positive bacteria, it largely inactive in killing Gram-negative bacteria. We have discovered addition of the nontoxic salt potassium iodide (100 mM) potentiates green light (540-nm)-mediated by up 6 extra logs with bacteria Escherichia coli and Pseudomonas aeruginosa, bacterium methicillin-resistant Staphylococcus aureus,...

A family of N-methylpyrrolidinium fullerene iodide salts has been intensively studied to determine their applicability in antimicrobial photodynamic therapy (APDT). This study examined vitro the efficacy a C60 functionalized with one methylpyrrolidinium group kill upon irradiation white light gram-negative and gram-positive bacteria, as well fungal cells, corresponding mechanism bactericidal action. The studies revealed that high antistaphylococcal could be linked ability photogenerate...

Multidrug resistance (MDR) remains a primary hindrance to curative cancer therapy. Thus, introduction of novel strategies overcome MDR is paramount therapeutic significance. Sequestration chemotherapeutics in lysosomes an established mechanism drug resistance. Here, we show that cells display marked increase lysosome number. We further demonstrate imidazoacridinones (IAs), which are cytotoxic fluorochromes, undergo dramatic compartmentalization because their hydrophobic weak base nature....

Melanosomes of the retinal pigment epithelium (RPE) are relatively long-lived organelles that theoretically susceptible to changes induced by exposure visible light. Here melanosomes were isolated from porcine RPE cells and subjected high intensity light determine effects illumination on melanosome structure content antioxidant properties melanin. As compared untreated melanosomes, illuminated granules showed morphologic consistent with photodegradation, which included variable reductions in...

The generation of singlet oxygen in aqueous colloids nanocrystalline TiO2 (anatase) modified by organic chelating ligands forming surface TiIV complexes was studied. Detailed studies revealed a plausible and to date unappreciated influence near-infrared irradiation on at the TiO2. To detect 1O2, direct indirect methods have been applied: photon counting technique enabling time-resolved measurements 1O2 phosphorescence, fluorescence product interaction with Singlet Oxygen Sensor Green (SOSG)....

Summary In this work, we examined photoreactivity of synthetic eumelanins, formed by autooxidation DOPA , or enzymatic oxidation 5,6‐dihydroxyindole‐2‐carboxylic acid and pheomelanins obtained 5‐ S ‐cysteinyldopa 1:1 mixture cysteine. Electron paramagnetic resonance oximetry spin trapping were used to measure oxygen consumption formation superoxide anion induced irradiation melanin with blue light, time‐resolved near‐infrared luminescence was employed determine the photoformation singlet...

The precise and real-time measurement of oxygen partial pressure (pO2) brings valuable information in many pathologies, including cancer. Low tumor pO2 (i.e., hypoxia) is connected to aggressiveness poor response therapy. quantification allows the evaluation treatment effectiveness. Electron Paramagnetic Resonance Imaging (EPRI), particularly Pulse EPRI, has emerged as an advanced three-dimensional (3D) method assessing tissue oxygenation vivo. This innovation was enabled by technological...

Singlet oxygen quantum yield (ΦΔ) is a critical parameter in photodynamic studies, particularly for evaluating photosensitizers' efficiency diverse applications such as therapy and environmental remediation. Standard photosensitizers, including Rose Bengal, Methylene Blue, porphyrins, are widely employed benchmarks determining ΦΔ. However, accurate determination of ΦΔ relies not only on the intrinsic properties these photosensitizers but also their experimental conditions, concentration....

Abstract The angiogenesis inhibitor sunitinib is a tyrosine kinase that acts mainly on the VEGF and PDGF pathways. We have previously shown sequestered in lysosomes of exposed tumor endothelial cells. This phenomenon part drug-induced resistance observed clinic. Here, we demonstrate when to light, causes immediate destruction lysosomes, resulting release cell death. hypothesized this photoactivation could be used as vaso-occlusive vascular-targeting approach treating cancer. Spectral...

Eumelanin photoprotects pigmented tissues from ultraviolet (UV) damage. However, UVA-induced tanning seems to result the photooxidation of preexisting melanin and does not contribute photoprotection. We investigated mechanism degradation 5,6-dihydroxyindole-2-carboxylic acid (DHICA)-melanin taking advantage its solubility in a neutral buffer using differential spectrophotometric method detect subtle changes structure. Our methodology is suitable for examining effects various agents that...

Skin cancer is the most common in U.S.A. and Europe. Its subtype, squamous skin carcinoma (SCC), if allowed to grow, has potential metastasize can become deadly. Currently, carbon nanomaterials are being developed treat due their attractive physicochemical biological properties such as an enhanced permeability effect ability produce reactive oxygen species. Here, we describe synthesis of two water-soluble aminofullerenes (MonoaminoC60 HexakisaminoC60), which were evaluated novel...

The abnormal susceptibility of red-haired individuals to UV-induced inflammation and skin cancers is commonly attributed the marked photoreactivity pheomelanin pigments, which would be responsible for sustained generation reactive oxygen species in following sun exposure. structural factors determining photolability remain mostly unknown. Here, we describe effects zinc ions, typically found at high levels red hair, enhancing both consumption superoxide production model pigments irradiation...

One of the factors determining efficient antimicrobial photodynamic inactivation (aPDI) is accumulation a light-activated compound, namely, photosensitizer (PS). Targeted PS recognition approach based on interaction between membrane receptor bacterial surface and PS, whereas compound efficiently accumulated by same mechanism as natural ligand. In this study, we showed that gallium mesoporphyrin IX (Ga3+MPIX) provided dual functionality─iron metabolism disruption properties in aPDI. Ga3+MPIX...

Melanin, particularly eumelanin, is commonly viewed as an efficient antioxidant and photoprotective pigment. Nonetheless, the ability of melanin to photogenerate reactive oxygen species sensitize formation cyclobutane pyrimidine dimers may contribute melanin-dependent phototoxicity. The phototoxic potential depends on a variety factors, including molecular composition, redox state, degree aggregation. Using complementary spectroscopic analytical methods we analyzed physicochemical properties...

Abstract Aging may significantly modify antioxidant and photoprotective properties of melanin in retinal pigment epithelium (RPE). Here, photoreactivity melanosomes (MS), isolated from younger older human donors with without added zeaxanthin α‐tocopherol, was analyzed by electron paramagnetic resonance oximetry, time‐resolved singlet oxygen phosphorescence, protein oxidation assay. The phototoxic potential ingested examined ARPE‐19 cells exposed to blue light. Phagocytosis FITC‐labeled...

The increasing applicability of antifungal treatments, the limited range available drug classes and emergence resistance in Candida spp. suggest need for new treatment options. To explore C. albicans photoinactivation, we examined nine structurally different imidazoacridinone derivatives as photosensitizing agents. most effective showed a >104-fold reduction viable cell numbers. fungicidal action three active compounds was compared at radiant powers(3.5 to 63 mW/cm2), this analysis indicated...

The risk of chronic oxidative stress in the retinal pigment epithelium (RPE) increases with age due to accumulation photoreactive lipofuscin (LFG). Here, we asked whether sublethal and weakly lethal photic stress, induced by irradiation ARPE-19 cells containing phagocytised LFG, affected cell specific phagocytic activity, which is critically important for proper functioning survival retina, if natural antioxidants could modify observed outcomes. preloaded LFG isolated from human donors...

Staphylococcus aureus is a key pathogen in atopic dermatitis (AD) pathogenicity. Over half of AD patients are carriers S. aureus. Clinical isolates derived from produce various staphylococcal enterotoxins, such as enterotoxin C or toxic shock syndrome toxin. The production these virulence factors correlated with more severe AD. In this study, we propose cationic heme-mimetic gallium porphyrin (Ga3+CHP), novel metalloporphyrin, an anti-staphylococcal agent that functions through dual...