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María E Alea-Reyes, Oriol Penon, Paula García Calavia, María J Marín, David A Russell, Lluïsa Pérez-García
HYPOTHESIS: Metalloporphyrins are extensively investigated for their ability to form reactive oxygen species and as potent photosensitisers for use in photodynamic therapy. However, their hydrophobicity generally causes solubility issues concerning in vivo delivery due to lack of distribution and low clearance from the body. Immobilising porphyrins on carriers, such as gold nanoparticles (GNP), can overcome some of these drawbacks. The mode of assembling the porphyrins to the carrier influences the properties of the resulting drug delivery systems...
March 7, 2018: Journal of Colloid and Interface Science
Jane Dobson, Genilson Fernandes de Queiroz, Jon P Golding
Photodynamic therapy (PDT) is an evolving method of treating superficial tumours that is non-invasive and carries minimal risk of toxicity. It combines tumour-selective photosensitiser dyes, tissue oxygen and targeted illumination to generate cytotoxic reactive oxygen species (ROS) within the tumour. In addition to directly acting on tumour cells, PDT damages and restricts tumour microvasculature, and causes a local inflammatory response that stimulates an immune response against the tumour. Unlike surgery or radiotherapy, the surrounding extracellular matrix is unaffected by PDT; thus, tissue healing is excellent and PDT seldom causes scars...
March 2018: Veterinary Journal
Y Lu, R Conway-Kenny, J Wang, X Cui, J Zhao, S M Draper
A series of new Ir(iii) complexes incorporating 3-(2-benzothiazolyl)-7-(diethylamino)coumarin (coumarin 6) and ethynylpyrene (EP) functionalised 1,10-phenanthroline (phen) were developed. [Ir(iii)(coumarin 6)2(3-EP-phen)](PF6) (Ir-3) proved to be the most promising material in triplet photosensitising applications. Highly absorbing at λ = 485 nm (ε = 1.31 × 105 M-1 cm-1), it exhibits high upconversion and singlet oxygen quantum yields (ΦUC = 27.5%, ΦΔ = 81.5%) and an exemplary upconversion capability (η = 3...
February 12, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Colin A Morton
Photodynamic therapy (PDT), using topically administered photosensitizing agents, is widely approved as a treatment for certain nonmelanoma skin cancers. As a tissue-sparing non-surgical modality, there is great potential for PDT to enhance the choice of therapies available to treat, and potentially prevent, skin cancer. Treatment-specific guidelines have assessed the evidence for various photosensitizing agents and light sources, dosimetry, and evaluate reported adverse effects. Discomfort is frequently experienced during treatment but no analgesia was required in most pivotal lesion-directed studies...
February 7, 2018: Giornale Italiano di Dermatologia e Venereologia: Organo Ufficiale, Società Italiana di Dermatologia e Sifilografia
Mateo Jelovica, Petra Grbčić, Martina Mušković, Mirela Sedić, Sandra Kraljević Pavelić, Martin Lončarić, Nela Malatesti
A series of N-methylated and N-oxidised tripyridyl porphyrins were synthesised, characterised, and their PDT activity was studied with six cell lines. All the tested porphyrins with a long alkyl chain, except one, were more efficient for PDT than an N-methylated hydrophilic porphyrin and N-oxidised porphyrin without the long alkyl chain. Generally, N-methylated tripyridyl porphyrins were more active than those N-oxidised, but IC50 values for phototoxicity of two N-oxides, named TOPyP3-C17 H33 O and TOPyP3-C17 H35 , were still in the nanomolar concentration range for most of the tested cell lines...
January 30, 2018: ChemMedChem
Rubén Ruiz-González, Francesca Setaro, Òscar Gulías, Montserrat Agut, Uwe Hahn, Tomás Torres, Santi Nonell
Correction for 'Cationic phthalocyanine dendrimers as potential antimicrobial photosensitisers' by Rubén Ruiz-González et al., Org. Biomol. Chem., 2017, 15, 9008-9017.
January 30, 2018: Organic & Biomolecular Chemistry
Irene Flickinger, Eva Gasymova, Simona Dietiker-Moretti, Alexander Tichy, Carla Rohrer Bley
Objectives The aim of this study was to evaluate the efficacy, long-term outcome and prognostic factors of feline squamous cell carcinoma (SCC) treated with photodynamic therapy (PDT). Methods Cats with histologically verified SCC of the head and neck received an intravenous injection of liposomal phosphorylated meta-tetra(hydroxylphenyl)chlorine (mTHPC) and 4 h later 652 nm light was delivered by a diode laser. One group received ⩽10 J/cm2, the other 20 J/cm2. Tumour response and duration were analysed with stage, tumour diameter, location and treatment intensity as prognostic factors...
January 1, 2018: Journal of Feline Medicine and Surgery
Junsi Wang, Yue Lu, William McCarthy, Robert Conway-Kenny, Brendan Twamley, Jianzhang Zhao, Sylvia M Draper
Novel mono- and di-nuclear Ru(ii) and Ir(iii) complexes, bearing a modified carbazole moiety are synthesised. In comparison to their mononuclear analogues, the homonuclear diatomic complexes (RuCRu and IrCIr), in which the carbazole containing-ligand functions as a bridge, display increased absorbance in the visible region, and give rise to higher singlet oxygen quantum yields.
January 12, 2018: Chemical Communications: Chem Comm
Jane C Quinn, Yuchi Chen, Belinda Hackney, Muhammad Shoaib Tufail, Leslie A Weston, Panayiotis Loukopoulos
BACKGROUND: Primary photosensitisation (PS) subsequent to ingestion of the pasture legume Biserrula pelecinus L. (biserrula) has recently been confirmed in grazing livestock. Given the potential utility of this pasture species in challenging climates, a grazing trial was undertaken to examine if both varieties 'Casbah' and 'Mauro' were able to cause photosensitisation in livestock, and if this could be mitigated by grazing in winter, or in combination with other common pasture species...
January 11, 2018: BMC Veterinary Research
Layla Mohammad-Hadi, Alexander J MacRobert, Marilena Loizidou, Elnaz Yaghini
Photodynamic therapy (PDT) is the subject of considerable research in experimental cancer models mainly for the treatment of solid cancerous tumours. Recent studies on the use of nanoparticles as photosensitiser carriers have demonstrated improved PDT efficacy in experimental cancer therapy. Experiments typically employ conventional monolayer cell culture but there is increasing interest in testing PDT using three dimensional (3D) cancer models. 3D cancer models can better mimic in vivo models than 2D cultures by for example enabling cancer cell interactions with a surrounding extracellular matrix which should enable the treatment to be optimised prior to in vivo studies...
January 8, 2018: Nanoscale
Bishakh Rout, Chi-Hsien Liu, Wei-Chi Wu
BACKGROUND: Photodynamic therapy has been studied by many studies as a method for inactivating bacterial growth. Workers have used planktonic bacterial as well as biofilm bacterial cultures to evaluate the potential of photodynamic therapy in inactivating bacteria. However, almost all the studies use a photosensitiser in aqueous solution, which could be detrimental to the efficiency of photodynamic therapy. METHODS: In this study, the photodynamic killing effect of toluidine blue O (TBO) has been investigated on Staphylococcal biofilms in -vitro...
December 13, 2017: Photodiagnosis and Photodynamic Therapy
Francesca Bryden, Antoine Maruani, João M M Rodrigues, Miffy H Y Cheng, Huguette Savoie, Andrew Beeby, Vijay Chudasama, Ross W Boyle
Exploitation of photosensitizers as payloads for antibody-based anticancer therapeutics offers a novel alternative to the small pool of commonly utilized cytotoxins. However, existing bioconjugation methodologies are incompatible with the requirement of increased antibody loading without compromising antibody function, stability, or homogeneity. Herein, we describe the first application of dendritic multiplier groups to allow the loading of more than 4 porphyrins to a full IgG antibody in a site-specific and highly homogeneous manner...
January 17, 2018: Bioconjugate Chemistry
Hussaini Majiya, Oluwapelumi O Adeyemi, Nicola J Stonehouse, Paul Millner
Singlet oxygen mediated oxidation has been shown to be responsible for photodynamic inactivation (PDI) of viruses in solution with photosensitisers such as 5, 10, 15, 20-tetrakis (1-methyl-4-pyridinio) porphyrin tetra p-toluenesulfonate (TMPyP). The capsids of non-enveloped viruses, such as bacteriophage MS2, are possible targets for viral inactivation by singlet oxygen oxidation. Within the capsid (predominantly composed of coat protein), the A-protein acts as the host recognition and attachment protein. The A-protein has two domains; an α-helix domain and a β-sheet domain...
January 2018: Journal of Photochemistry and Photobiology. B, Biology
Lisa Wright, Daniel Baptista-Hon, Fiona Bull, Faith Dalgaty, Michael Gallacher, Sally H Ibbotson, Tim G Hales
Phototoxicity-induced pain is a major clinical problem triggered by light acting on photosensitising drugs or endogenous porphyrins, notably protoporphyrin IX (PpIX), an intermediary in heme biosynthesis. Protoporphyrin IX accumulates in individuals with erythropoietic protoporphyria and is elevated during photodynamic therapy subsequent to application of 5-aminolevulinic acid (ALA). Pain occurs during irradiation of PpIX and responds poorly to conventional analgesics. Our objective was to develop a model of PpIX phototoxicity pain and investigate the potential of menthol as an analgesic...
November 25, 2017: Pain
Devashish Sengupta, Zeaul Hoque Mazumdar, Avinaba Mukherjee, Debdulal Sharma, Amit Kumar Halder, Samita Basu, Tarun Jha
Amphiphilic porphyrin photosensitisers (PSs) having combinations of directly substituted pyridyl group(s) at the meso-position of a porphyrin macrocycle, and/or indirectly linked pyridyl groups as benzamide derivatives are reported. The compounds 5,10,15,20-tetrakis-(4-pyridylbenzamide)porphyrin (A.2), 5,10,15,20-tetra[N-(pyridine-4-yl)benzamidium] porphyrin (A.3), 5-mono-(4-pyridyl)-10,15,20-tris-(4-pyridylbenzamide)porphyrin (B.2) and 5-mono-(4-methylpyridinium)-10,15,20-tris-(4-pyridiniumbenzamide)porphyrin (B...
November 13, 2017: Journal of Photochemistry and Photobiology. B, Biology
Katherine L Orchard, Daisuke Hojo, Katarzyna P Sokol, Meng-Ju Chan, Naoki Asao, Tadafumi Adschiri, Erwin Reisner
Visible-light driven H2 evolution in water is achieved using catechol-photosensitised TiO2 nanoparticles with a molecular nickel catalyst. Layer-by-layer immobilisation of catechol-TiO2 onto tin-doped indium oxide electrodes generates photocathodic currents in the presence of an electron acceptor. This approach represents a new strategy for controlling photocurrent direction in dye-sensitised photoelectrochemical applications.
November 23, 2017: Chemical Communications: Chem Comm
F Bolze, S Jenni, A Sour, V Heitz
Two-photon excitation has attracted the attention of biologists, especially after the development of two-photon excited microscopy in the nineties. Since then, new applications have rapidly emerged such as the release of biologically active molecules and photodynamic therapy (PDT) using two-photon excitation. PDT, which requires a light-activated drug (photosensitiser), is a clinically approved and minimally invasive treatment for cancer and for non-malignant diseases. This feature article focuses on the engineering of molecular two-photon photosensitisers for PDT, which should bring important benefits to the treatment, increase the treatment penetration depth with near-infrared light excitation, improve the spatial selectivity and reduce the photodamage to healthy tissues...
November 30, 2017: Chemical Communications: Chem Comm
Muhammad Qutayba Almerie, Gemma Gossedge, Kathleen E Wright, David G Jayne
BACKGROUND: Peritoneal carcinomatosis results when tumour cells implant and grow within the peritoneal cavity. Treatment and prognosis vary based on the primary cancer. Although therapy with intention-to-cure is offered to selective patients using cytoreductive surgery with chemotherapy, the prognosis remains poor for most of the patients. Photodynamic therapy (PDT) is a cancer-therapeutic modality where a photosensitiser is administered to patients and exerts a cytotoxic effect on cancer cells when excited by light of a specific wavelength...
December 2017: Photodiagnosis and Photodynamic Therapy
Paul A Scattergood, Paul I P Elliott
The photophysical properties of transition metal complexes have long attracted interest in the literature with significant research activity during the past two to three decades due to the potential exploitation of these materials in solar energy conversion, light-emitting technology, luminescence biological imaging and photodynamic therapeutic applications to name but a few. Since the advent of the facile preparation of 1,2,3-triazole-based compounds through copper(i)-catalysed cycloaddition, ligands based on this heterocycle have received widespread attention in coordination chemistry...
December 21, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Michael Glueck, Barbara Schamberger, Peter Eckl, Kristjan Plaetzer
Outbreaks of foodborne diseases are regularly reported worldwide. In particular, uncooked plant food is considered risky in terms of microbiological safety. Food is also the most important transmission route for resistant microorganisms from animals to humans. Photodynamic Decontamination (PDc) of foodstuff was recently introduced as a novel approach for increasing microbiological food safety. We investigated the efficiency of PDc on plant food with different geometries (flat, spherical and complex) using a two-dimensional LED array as a light source (435 nm, 33...
December 6, 2017: Photochemical & Photobiological Sciences
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