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Angelo Lanzilotto, Myrto Kyropoulou, Edwin C Constable, Catherine E Housecroft, Wolfgang P Meier, Cornelia G Palivan
A new water-soluble photocatalyst for singlet oxygen generation is presented. Its absorption extends to the red part of the spectrum, showing activity up to irradiation at 660 nm. Its efficiency has been compared to that of a commercial analogue (Rose Bengal) for the oxidation of L-methionine. The quantitative and selective oxidation was promising enough to encapsulate the photocatalyst in polymersomes. The singlet oxygen generated in this way can diffuse and remain active for the oxidation of L-methionine outside the polymeric compartment...
December 7, 2017: Journal of Biological Inorganic Chemistry: JBIC
Vijay Chudasama, Francesca Bryden, Huguette Savoie, Antoine Maruani, Miffy Cheng, Andrew Beeby, Joao Rodrigues, Ross W Boyle
Exploitation of photosensitisers as payloads for antibody-based anti-cancer therapeutics offers a novel alternative to the small pool of commonly-utilised 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...
December 7, 2017: Bioconjugate Chemistry
Antonio Di Dato, Alessandra Cunsolo, Marco Persico, Anna Maria Santoro, Alessandro D'Urso, Danilo Milardi, Roberto Purrello, Manuela Stefanelli, Roberto Paolesse, Grazia R Tundo, Diego Sbardella, Caterina Fattorusso, Massimo Coletta
The importance of allosteric proteasome inhibition in the treatment of cancer is becoming increasingly evident. Motivated by this urgent therapeutic need, we have recently identified cationic porphyrins as a highly versatile class of molecules able to regulate proteasome activity by interfering with gating mechanisms. In the present study, the mapping of electrostatic contacts bridging the regulatory particles with the α-rings of the human 20S proteasome led us to the identification of (meso-tetrakis(4-N-methylphenyl pyridyl)-porphyrin (pTMPyPP4) as a novel non-competitive inhibitor of human 20S proteasome...
December 6, 2017: Scientific Reports
Lorenzo Cupellini, Samuele Giannini, Benedetta Mennucci
Photoinduced electron transfer (ET), hole transfer (HT), charge recombination (CR) and energy transfer (EET) are fundamental mechanisms, which occur in both natural and artificial light harvesting systems. Here, we present a computational strategy which determines ET, HT, CR and EET rates in a consistent way and merges them in a kinetic model to reproduce the net excited state dynamics. The effects of the solvent are included in all steps of the calculations making the present strategy a useful tool for a rational design of charge and energy transfer processes in complex systems...
December 6, 2017: Physical Chemistry Chemical Physics: PCCP
Joon-Heum Park, Lien H Tran, Sunyo Jung
Possible crosstalk between the carotenoid and porphyrin biosynthetic pathways under photooxidative conditions was investigated by using their biosynthetic inhibitors, norflurazon (NF) and oxyfluorfen (OF). High levels of protoporphyrin IX (Proto IX) accumulated in rice plants treated with OF, whereas Proto IX decreased in plants treated with NF. Both NF and OF treatments resulted in greater decreases in MgProto IX, MgProto IX methyl ester, and protochlorophyllide. Activities and transcript levels of most porphyrin biosynthetic enzymes, particularly in the Mg-porphyrin branch, were greatly down-regulated in NF and OF plants...
2017: Frontiers in Plant Science
Takahiko Kojima, Wataru Suzuki, Hiroaki Kotani, Tomoya Ishizuka, Yoshihito Shiota, Kazunari Yoshizawa
The two-electron reduction of a diprotonated dodecaphenylporphyrin derivative by Na2S2O4 gave a corresponding isophlorin (Iph) selectively. Formation of Iph was confirmed by spectroscopic measurements and the isolation of tetra-methylated Iph. Further reduction of Iph proceeded to form an unprecedented four-electron reduced porphyrin (IphH2), which is fully characterized by spectroscopic and X-ray crystallographic analysis. IphH2 with a unique conformation is capable of performing a reversibility to reproduce the starting porphyrin by the chemical oxidation, which acts as a proton-coupled four-electron reversible redox system...
December 5, 2017: Angewandte Chemie
Xin Xu, Yongjuan Li, Qiujun Liang, Ziyuan Song, Fangfang Li, Hua He, Jinhui Wang, Lipeng Zhu, Zhifeng Lin, Lichen Yin
The development of robust and nontoxic membrane-penetrating materials is highly demanded for non-viral gene delivery. Herein, a photosensitizer (PS)-embedded, star-shaped helical polypeptide was developed, which combines the merit of multivalency-enhanced intracellular DNA uptake and light-strengthened endosomal escape to enable highly efficient gene delivery with low toxicity. 5,10,15,20-Tetrakis-(4-aminophenyl) porphyrin (TAPP) as a selected PS initiated ring-opening polymerization (ROP) of N-carboxyanhydride (NCA), and yielded star-shaped helical polypeptide after side-chain functionalization with guanidine groups...
December 5, 2017: ACS Applied Materials & Interfaces
Pierre D Harvey, Hu Lei, Paul-Ludovic Karsenti
The notoriously non-luminescent uncycled azophenine (Q) was harnessed with Bodipy and zinc(II)porphyrin antennas to probe its fluorescence properties, its ability to act as a singlet excited state energy acceptor and to mediate the transfer. Two near-IR emissions are depicted from time-resolved fluorescence spectroscopy, which are most likely due to the presence of tautomers of very similar calculated total energies (350 cm-1; DFT; B3LYP). The rates for energy transfer, kET(S1), for 1Bodipy*→Q are in the order of 1010-1011 s-1 and are surprisingly fast when considering the low absorptivity properties of the lowest energy charge transfer excited state of azophenine...
December 3, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Alexandra Rieger, Stephan Schnidrig, Benjamin Probst, Karl-Heinz Ernst, Christian Wäckerlin
Surface adsorbed macrocycles exhibit a number of interesting physical and chemical properties, many of them are determined by their transition metal centers. Here, the hierarchical exchange of the central metal atom in such surface adsorbed complexes is demonstrated, specifically in the porphyrin-like macrocycle pyrphyrin adsorbed on Cu(111). Using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS), we show that Cu as central metal atom is easily exchanged with Ni or Fe atoms supplied in trace amounts to the surface...
December 4, 2017: Journal of Physical Chemistry Letters
Tzu-Yen Huang, Chung-Wei Kung, Yu-Te Liao, Sheng-Yuan Kao, Mingshan Cheng, Ting-Hsiang Chang, Joel Henzie, Hatem R Alamri, Zeid A Alothman, Yusuke Yamauchi, Kuo-Chuan Ho, Kevin C-W Wu
With the aim of a reliable biosensing exhibiting enhanced sensitivity and selectivity, this study demonstrates a dopamine (DA) sensor composed of conductive poly(3,4-ethylenedioxythiophene) nanotubes (PEDOT NTs) conformally coated with porphyrin-based metal-organic framework nanocrystals (MOF-525). The MOF-525 serves as an electrocatalytic surface, while the PEDOT NTs act as a charge collector to rapidly transport the electron from MOF nanocrystals. Bundles of these particles form a conductive interpenetrating network film that together: (i) improves charge transport pathways between the MOF-525 regions and (ii) increases the electrochemical active sites of the film...
November 2017: Advanced Science (Weinheim, Baden-Wurttemberg, Germany)
Maryam Khosravi, Rahmatollah Rahimi, Jalal Pourahmad, Mohammad Hadi Zarei, Mahboubeh Rabbani
In this research, dipeptide (his-β-alanine) and porphyrin derivatives were choosen for comparing chelating ability of toxic metals such as Al3+, Cu2+, Hg2+ and Pb2+in-vitro. The reason for choosing these two compounds is that both of them are naturally present in biological systems and comparison of chelating ability of these two compounds has not yet been done. Synthesis and comparison of kinetic study of dipeptide (his-β-alanine), meso-tetrakis(4-trimethylanilinium) porphyrin (TAPP) and Tetrakis(4-sulfonatophenyl)porphyrin (TPPS4) were carried out by our team...
2017: Iranian Journal of Pharmaceutical Research: IJPR
Malak Charara, Artak Tovmasyan, Ines Batinic-Haberle, James Craik, Ludmil Benov
Increased interest in clinical application of photodynamic therapy (PDT) in various medical fields poses a demand for better understanding of processes triggered by photo-treatment. Most of the work on PDT performed so far has focused on the immediate effects of photo-treatment. It is generally accepted that cellular damage occurs during light exposure and within a short period thereafter. If cells are not killed during the PDT, they might recover, depending on the extent of the photo-induced damage. Little is known, however, about the relationship between the properties of photosensitizers (PSs) and the delayed consequences of PDT...
2017: PloS One
Karen Mary Mantovani, Kátia Cristina Molgero Westrup, Renaldo Marcos da Silva Junior, Silvia Jaerger, Fernando Wypych, Shirley Nakagaki
Several functional hybrid materials have been reported as immobilized porphyrin derivatives in various organic and inorganic host materials (polymers, mineral clays, silica, etc.), with potential applications in various fields, such as photochemistry, electrochemistry and heterogeneous catalysis. Layered double hydroxides (LDHs), commonly known as hydrotalcite-like materials, have also been analyzed for use as supports for metallocomplexes. Recently, nanocomposite materials with a core-shell structure produced by combining two kinds of nanometer-size materials have received considerable attention, since the use of these materials is a promising strategy to prevent the aggregation and self-oxidation of molecules, reducing the catalytic activity...
December 4, 2017: Dalton Transactions: An International Journal of Inorganic 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...
November 26, 2017: Journal of Photochemistry and Photobiology. B, Biology
Kai Liu, Han Zhang, Ruirui Xing, Qianli Zou, Xuehai Yan
Biomimetic organization provides a promising strategy to develop functional materials and understand biological processes. However, how to mimic complex biological systems using simple biomolecular units remains a great challenge. Herein, we design and fabricate a biomimetic cyanobacteria model based on self-integration of small bioinspired molecules, including amphiphilic amino acid, 3,4-dihydroxyphenylalanine (DOPA), and metalloporphyrin and Co3O4 nanoparticles (NPs), with the assistance of chemical conjugation and molecular self-assembly...
December 1, 2017: ACS Nano
Dandan Luo, Shreya Goel, Hai-Jun Liu, Kevin A Carter, Dawei Jiang, Jumin Geng, Christopher J Kutyreff, Jonathan W Engle, Wei-Chiao Huang, Shuai Shao, Chao Fang, Weibo Cai, Jonathan F Lovell
Doxorubicin (Dox)-loaded stealth liposomes (similar to those in clinical use) can incorporate small amounts of porphyrin-phospholipid (PoP), to enable chemophototherapy (CPT). PoP is also an intrinsic and intrabilayer 64Cu chelator, although how radiolabeling impacts drug delivery has not yet been assessed. Here, we show that 64Cu can radiolabel the stable bilayer of preformed Dox-loaded PoP liposomes with inclusion of 1 % ethanol, without inducing drug leakage. Dox-PoP liposomes labeled with intrabilayer copper behaved nearly identically to unlabeled ones in vitro and in vivo with respect to physical parameters, pharmacokinetics and CPT efficacy...
December 1, 2017: ACS Nano
Atsuhiro Osuka, Kenichi Kato, Ko Furukawa, Tadashi Mori
Stable helical radicals are promising multi-functional molecules in light of intriguing magnetic and chiroptical properties. Attempts were made to extend diphenylmethyl-fused NiII porphyrin radical to helical system as the first air-stable organic neutral helical radicals. Intramolecular Pd-catalyzed twofold C-H arylation of methyl- or methoxy-introduced meso-diphenylmethyl NiII porphyrins gave a mixture of the target and rearranged radicals. Oxidative fusion reaction of meso-(bis(1-naphthyl)methyl) NiII porphyrins provided doubly fused NiII porphyrin radicals...
November 30, 2017: Chemistry: a European Journal
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
Mary-Ambre Carvalho, Hervé Dekkiche, Lydia Karmazin, Fabien Sanchez, Bruno Vincent, Masatoshi Kanesato, Yoshihiro Kikkawa, Romain Ruppert
Several porphyrin dimers linked by metal ions were prepared. One trimeric compound was also isolated and one porphyrin dimer linked by palladium(II) could be structurally characterized. In solution, the size of the new compounds was estimated by DOSY NMR techniques. These compounds all contained long aliphatic chains (O-C12H25), which were used to assemble them at a highly oriented pyrolytic graphite (HOPG)/liquid interface. The highly ordered arrays were visualized by scanning tunneling microscopy (STM).
December 1, 2017: Inorganic Chemistry
Rebba C Boswell-Casteel, Yu Fukuda, John D Schuetz
Recent findings have discovered how insufficiency of ATP-binding cassette (ABC) transporter, ABCB6, can negatively impact human health. These advances were made possible by, first, finding that ABCB6 deficiency was the genetic basis for some severe transfusion reactions and by, second, determining that functionally impaired ABCB6 variants enhanced the severity of porphyria, i.e., diseases associated with defects in heme synthesis. ABCB6 is a broad-spectrum porphyrin transporter that is capable of both exporting and importing heme and its precursors across the plasma membrane and outer mitochondrial membrane, respectively...
November 30, 2017: AAPS Journal
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