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https://www.readbyqxmd.com/read/28821011/the-photodynamic-action-of-pheophorbide-a-induces-cell-death-through-oxidative-stress-in-leishmania-amazonensis
#1
Nathielle Miranda, Hélito Volpato, Jean Henrique da Silva Rodrigues, Wilker Caetano, Tânia Ueda-Nakamura, Sueli de Oliveira Silva, Celso Vataru Nakamura
Leishmaniasis is a disease caused by hemoflagellate protozoa, affecting millions of people worldwide. The difficulties of treating patients with this parasitosis include the limited efficacy and many side effects of the currently available drugs. Therefore, the search for new compounds with leishmanicidal action is necessary. Photodynamic therapy has been studied in the medical field because of its selectivity, utilizing a combination of visible light, a photosensitizer compound, and singlet oxygen to reach the area of treatment...
August 11, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28820580/enhanced-fluorescence-emission-and-singlet-oxygen-generation-of-photosensitizers-embedded-in-injectable-hydrogels-for-imaging-guided-photodynamic-cancer-therapy
#2
Liu-Yuan Xia, Xiaodong Zhang, Meng Cao, Zhan Chen, Fu-Gen Wu
Benefiting from their inherent localized and controlled release properties, hydrogels are ideal delivery systems for therapeutic drugs or nanoparticles. In particular, the applications of hydrogels for the delivery and release of photo-responsive drugs or nanoparticles are receiving increasing attention. However, the effect of the hydrogel matrix on the fluorescence emission and singlet oxygen generation efficiency of the embedded photosensitizers (PSs) has not been clarified. Herein, meso-tetrakis (1-methylpyridinium-4-yl) porphyrin (TMPyP) as a water-soluble PS is encapsulated into an injectable hydrogel formed by glycol chitosan and dibenzaldehyde-terminated telechelic poly(ethylene glycol)...
August 18, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28820528/deciphering-the-photosensitization-mechanisms-of-hypericin-towards-biological-membranes
#3
Hugo Gattuso, Marco Marazzi, François Dehez, Antonio Monari
Resorting to state-of-the art molecular modeling and simulation techniques we provide full characterization of the photophysical properties of the naturally occurring hypericin chromophore, currently used in photodynamic therapy. In particular, we reveal the different photophysical pathways leading to intersystem-crossing and hence, triplet manifold population that is necessary for the subsequent production of singlet oxygen. In particular we identify an extended region of quasi-degeneracy between the first singlet excited state and three triplet state surfaces...
August 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28819667/synthesis-and-optical-and-electrochemical-properties-of-a-phenanthrodithiophene-fused-bibenzo-c-thiophene-derivative
#4
Yousuke Ooyama, Toshiaki Enoki, Satoshi Aoyama, Joji Ohshita
We designed and developed a fused-bibenzo[c]thiophene, namely, 2,9-bis(tert-butyldimethylsilyl)phenanthro[9,8-bc:10,1-b'c']dithiophene (PHDT-Si), as a new π-building block in the emitters, photosensitizers and semiconductors for organic optoelectronic devices. Based on photophysical (photoabsorption, fluorescence and time-resolved fluorescence spectroscopy) and electrochemical measurements (cyclic voltammetry), and density functional theory (DFT) calculations, this work reveals that the fused-bibenzo[c]thiophene PHDT-Si, which is prepared by an efficient synthesis method, has a rigid, high planar and expanded π-conjugation structure, and possesses intense photoabsorption and fluorescence properties (λ = 598 nm (εmax = 41 000 M(-1) cm(-1)) and λ = 613 nm (Φf = 0...
August 18, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/28819665/efficient-photoelectrochemical-water-splitting-on-ultrasmall-defect-rich-taox-nanoclusters-enhanced-by-size-selected-pt-nanocluster-promoters
#5
Saurabh Srivastava, Joseph Palathinkal Thomas, Nina Heinig, Marwa Abd-Ellah, Md Anisur Rahman, Kam Tong Leung
Formation of nanoclusters has attracted a lot of attention in recent years because of their distinct properties from isolated atoms and bulk solids. Here, we focus on the catalytic properties of supported transition metal oxide nanoclusters, such as TaO2, with a well-defined size distribution below 10 nm. We show that their catalytic performance can be greatly enhanced by introducing a reaction promoter such as Pt. Different combinations of precisely size-selected, defect-rich TaOx and Pt nanoclusters are produced by a gas-phase aggregation technique in a special DC magnetron sputtering system...
August 18, 2017: Nanoscale
https://www.readbyqxmd.com/read/28819460/a-tumor-ph-responsive-supramolecular-photosensitizer-for-activatable-photodynamic-therapy-with-minimal-in-vivo-skin-phototoxicity
#6
Xingshu Li, Bi-Yuan Zheng, Mei-Rong Ke, Yongfan Zhang, Jian-Dong Huang, Juyoung Yoon
A major challenge in photodynamic therapy (PDT) is the development of new tumor-targeting photosensitizers. The tumor-specific activation is considered to be an effective strategy for designing these photosensitizers. Herein, we describe a novel tumor-pH-responsive supramolecular photosensitizer, LDH-ZnPcS8, which is not photoactive under neutral conditions but is precisely and efficiently activated in a slightly acidic environment (pH 6.5). LDH-ZnPcS8 is prepared by using a simple coprecipitation method based on the electrostatic interaction between negatively charged octasulfonate-modified zinc(II) phthalocyanine (ZnPcS8) and cationic hydroxide layers of layered double hydroxide (LDH)...
2017: Theranostics
https://www.readbyqxmd.com/read/28819397/iron-chelators-and-exogenic-photosensitizers-synergy-through-oxidative-stress-gene-expression
#7
Anna Mrozek-Wilczkiewicz, Katarzyna Malarz, Marzena Rams-Baron, Maciej Serda, Daniela Bauer, Franz-Peter Montforts, Alicja Ratuszna, Thomas Burley, Jaroslaw Polanski, Robert Musiol
In non-invasive anticancer photodynamic therapy (PDT), a nontoxic photosensitizer (PS), which is activated by visible light, is used as a magic bullet that selectively destroys cancer cells. Recently, we described the combined therapy of 5-aminolevulinic acid (ALA-PDT) with thiosemicarbazone (TSC), i.e. an iron-chelating agent. This resulted in a strong synergistic effect. Herein, we investigated a novel strategy using a combination of PDT consist of the xenobiotic-porphyrin type PS with TSC. We observed a synergistic effect for all of the pairs of TSC-PS...
2017: Journal of Cancer
https://www.readbyqxmd.com/read/28819103/mass-production-of-polymer-nano-wires-filled-with-metal-nano-particles
#8
Nino Lomadze, Alexey Kopyshev, Matias Bargheer, Markus Wollgarten, Svetlana Santer
Despite the ongoing progress in nanotechnology and its applications, the development of strategies for connecting nano-scale systems to micro- or macroscale elements is hampered by the lack of structural components that have both, nano- and macroscale dimensions. The production of nano-scale wires with macroscale length is one of the most interesting challenges here. There are a lot of strategies to fabricate long nanoscopic stripes made of metals, polymers or ceramics but none is suitable for mass production of ordered and dense arrangements of wires at large numbers...
August 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28816311/hierarchical-core-shell-sio2-pda-biobr-microspheres-with-enhanced-visible-light-driven-photocatalytic-performance
#9
Shuai-Ru Zhu, Qi Qi, Wen-Na Zhao, Meng-Ke Wu, Yuan Fang, Kai Tao, Fei-Yan Yi, Lei Han
To explore catalysts combining highly accessible specific surface areas with low recombination of the photo-induced electron-hole pairs, a novel SiO2@PDA@BiOBr composite photocatalyst with a hierarchical core-shell structure was prepared by a facile solvothermal method. The catalyst shows a superior performance on photodegradation of Rhodamine B under visible light irradiation, especially for SiO2@PDA-2@BiOBr with the reactant kinetics constant (k = 0.0487 min(-1)). The enhanced photocatalytic performance of SiO2@PDA-2@BiOBr was ascribed to the decreased band-gap, higher surface area, and effectively photo-generated electron-hole pairs by the introduction of polydopamine (PDA)...
August 17, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28815926/catalytic-conversion-of-dinitrogen-into-ammonia-under-ambient-reaction-conditions-by-using-proton-source-from-water
#10
Yoshiaki Tanabe, Kazuya Arashiba, Kazunari Nakajima, Yoshiaki Nishibayashi
Molybdenum-catalyzed conversion of molecular dinitrogen into ammonia under ambient reaction conditions has been achieved by using a proton source generated in situ from the ruthenium-catalyzed oxidation of water in combination with visible light and a photosensitizer. The preset reaction system is considered as a new model for the nitrogen fixation by photosynthetic bacteria.
August 17, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28815861/radiation-and-chemotherapy-with-no-excessive-toxicity-in-a-patient-with-human-papillomavirus-related-tonsillar-cancer-and-porphyria-cutanea-tarda-case-report-and-literature-review
#11
James K Russo, Annie Braseth
BACKGROUND: Porphyria is a condition of cutaneous photosensitivity. It is unclear if radiotherapy (RT) is safe in patients with porphyria. METHODS: We report a patient case with uncontrolled porphyria cutanea tarda treated with chemoradiation for p16-positive oropharyngeal cancer. Given the scarcity of data on this subject, we also conducted a literature review on the topic of radiation in patients with porphyria. RESULTS: The patient in our study did not experience any unusual acute or late toxicity, despite receiving a high dose of cutaneous radiation...
August 16, 2017: Head & Neck
https://www.readbyqxmd.com/read/28815553/osteoporosis-in-erythropoietic-protoporphyria-patients
#12
M Biewenga, R H S Matawlie, E C H Friesema, H Koole-Lesuis, M Langeveld, J H P Wilson, J G Langendonk
BACKGROUND: Erythropoietic protoporphyria is a rare metabolic disease with painful photosensitivity due to protoporphyrin IX accumulation, resulting in lifelong light avoidance behaviour. OBJECTIVES: The aim of this study was to evaluate bone mineral density and known osteoporosis risk factors in erythropoietic protoporphyria patients. METHODS: In this cross-sectional study all erythropoietic protoporphyria patients attending the Erasmus MC outpatient clinic that had undergone bone mineral density measurements were included...
August 17, 2017: British Journal of Dermatology
https://www.readbyqxmd.com/read/28813066/multivalent-mesoporous-silica-nanoparticles-photo-delivering-nitric-oxide-with-carbon-dots-as-fluorescence-reporters
#13
Damien Afonso, Sabrina Valetti, Aurore Fraix, Claudia Bascetta, Salvatore Petralia, Sabrina Conoci, Adam Feiler, Salvatore Sortino
Amino-terminated mesoporous silica nanoparticles embedding carbon dots (MSCD) formed by calcination were functionalized with a nitric oxide (NO) photodonor (1) to give a robust MSCD-1 conjugate. The intense fluorescence of MSCDs was strongly quenched in MSCD-1 by effective energy transfer. Visible light excitation of MSCD-1 liberates NO, suppresses the energy transfer mechanism and leads to concomitant fluorescence restoration of the MSCD scaffold, which acts as an optical reporter for the released NO. The MSCD-1 hybrid is also able to encapsulate the highly hydrophobic photosensitizer temoporfin, preserving the fluorescence reporting function...
August 16, 2017: Nanoscale
https://www.readbyqxmd.com/read/28812067/nonlinear-imaging-microscopy-for-assessing-structural-and-photochemical-modifications-upon-laser-removal-of-dammar-varnish-on-photosensitive-substrates
#14
M Oujja, S Psilodimitrakopoulos, E Carrasco, M Sanz, A Philippidis, A Selimis, P Pouli, G Filippidis, M Castillejo
The nonlinear optical microscopy (NLM) modalities of Multi-Photon Excited Fluorescence (MPEF) and Third Harmonic Generation (THG) have been combined in this work to characterize as a function of depth with micrometric resolution the type and extent of morphological and photochemical modifications that take place upon ultraviolet (UV) pulsed laser removal of a dammar varnish layer applied on a photosensitive substrate. The latter consists on a layer of the synthetic polymer poly-methyl methacrylate doped with a photosensitizer, the aromatic compound 1,4-di[2-(5-phenyloxazolyl)] benzene, that strongly fluoresces upon UV light illumination...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28811224/hypericin-cytotoxicity-in-tumor-and-non-tumor-cell-lines-a-chemometric-study
#15
Joyce Laura da Silva Gonçalves, Claudia Bernal, Hidetake Imasatoa, Janice Rodrigues Perussi
Hypericin (HY) is an excellent photoactive compound that has been investigated for the photodynamic treatment of cancer as well as for microorganisms inactivation. In this study, chemometric analysis was applied for the first time on photodynamic assays to investigate the cytotoxicity of HY in tumor (HEp-2) and non-tumor (Vero and HUVEC) cell lines. The experimental planning was based on eight assays using the 2(3) full factorial design combining three important variables for PDT: photosensitizer concentrations, incubation time of cells in HY solutions and employed light dose (=590±10nm)...
August 12, 2017: Photodiagnosis and Photodynamic Therapy
https://www.readbyqxmd.com/read/28811165/dicyanomethylene-substituted-benzothiazole-squaraines-the-efficiency-of-photodynamic-therapy-in-vitro-and-in-vivo
#16
Yongbiao Wei, Xiaoxiao Hu, Luyao Shen, Bing Jin, Xiangjun Liu, Weihong Tan, Dihua Shangguan
The lack of ideal photosensitizers limits the clinicalapplication of photodynamic therapy (PDT). Here we report the PDT efficiency of dicyanomethylene substituted benzothiazole squaraine derivatives. This class of squaraine derivatives possess strong absorption and long excitation and emission wavelengths (ex/em, 685/720nm). They show negligible dark toxicity, but can generate singlet oxygen under irradiation resulting in the apoptosis and necrosis of cells (phototoxicity). Changing the side chains of these compounds greatly influences their albumin-binding rate, cellular uptake and their phototoxicity...
August 9, 2017: EBioMedicine
https://www.readbyqxmd.com/read/28809962/nonlinear-behavior-and-fluctuation-induced-dynamics-in-the-photosensitive-belousov-zhabotinsky-reaction
#17
Valérie Voorsluijs, Ioannis G Kevrekidis, Yannick De Decker
The photosensitive Belousov-Zhabotinsky (pBZ) reaction has been used extensively to study the properties of chemical oscillators. In particular, recent experiments revealed the existence of complex spatiotemporal dynamics for systems consisting of coupled micelles (V < 10(-21) L) or droplets (V ≈ [10(-8)-10(-11)] L) in which the pBZ reaction takes place. These results have been mostly understood in terms of reaction-diffusion models. However, in view of the small size of the droplets and micelles, large fluctuations of concentrations are to be expected...
August 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28809498/bodipy-anthracene-dyads-as-triplet-photosensitizers-effect-of-chromophore-orientation-on-triplet-state-formation-efficiency-and-application-in-triplet-triplet-annihilation-upconversion
#18
Zhijia Wang, Jianzhang Zhao
Bodipy-anthracene dyads with two chromophores assuming orthogonal geometry to enhance the spin-orbital charge-transfer intersystem crossing (SOCT-ISC) were prepared. The photosensitizers show strong absorption of visible light, efficient triplet-state formation (quantum yield 90%), and a long-lived triplet state (85 μs). The dipole moment orientation exerts significant effect on the ISC efficiency. It is also the first time that photosensitizers based on SOCT-ISC were used for triplet-triplet annihilation upconversion...
August 15, 2017: Organic Letters
https://www.readbyqxmd.com/read/28808835/carbazole-substituted-bodipys-synthesis-computational-electrochemical-and-dssc-studies
#19
Praseetha E Kesavan, Raghu Nath Behera, Shigeki Mori, Iti Gupta
Carbazole and p-anisyl substituted BODIPY dyes with a cyanoacetic acid anchoring group have been prepared and their spectral, electrochemical properties and photosensitizing potential in DSSC have been evaluated. X-ray structure of N-phenylcarbazole substituted BODIPY revealed lower torsion angle between BODIPY plane and carbazole plane, suggesting increased communication between the two units. DFT studies indicated effective electronic interactions between the BODIPY unit and carbazole substituents. The N-butylcarbazole and N-phenylcarbazole substituted BODIPYs showed anodic shifts in their reduction potentials, indicating facile reduction process...
August 14, 2017: Journal of Fluorescence
https://www.readbyqxmd.com/read/28807774/chlorin-e6-mediated-photodynamic-therapy-promotes-collagen-production-and-suppresses-mmps-expression-via-modulating-ap-1-signaling-in-p-acnes-stimulated-hacat-cells
#20
A-Reum Ryu, Mi-Young Lee
BACKGROUND: Photodynamic therapy (PDT) is a clinically approved therapeutics for cancers and non-neoplastic diseases, based on the use of a photosensitizer activated by a light. The feasibility of PDT depends on several factors, such as PDT dose, photosensitizer efficacy, type of light source, and target tissue irradiated. METHODS: In this study, the second generation photosensitizer chlorin e6 (Ce6) and halogen light were used to investigate their PDT effect on the collagen production and MMPs expression of heat killed P...
August 11, 2017: Photodiagnosis and Photodynamic Therapy
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