Tryptophan Quenching of Zinc‐Phthalocyanine and Porphycene Fluorescence in Micellar CTAC

Daraio, Marta E.; Völker, Axel; Aramendı́a, Pedro F.; Román, Enrique San

doi:10.1111/j.1751-1097.1998.tb05213.x

Cited by 12 publications

(9 citation statements)

References 43 publications

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“…In previous studies, electron transfer quenching of porphycene or phthalocyanine-excited states by Trp has been postulated. 33,34 Also, the photosensitized oxidation of Trp was found to be more than two orders of magnitude more efficient via electron transfer than via O 2 ( 1 D g ). 35 Since cationic porphyrin can interact with Trp, probably by electrostatic attraction, an electron transfer pathway may also be contributing together with type II photoprocess to their decomposition.…”

Section: Spectroscopic Studiesmentioning

confidence: 99%

Photodynamic inactivation of Escherichia coli by novel meso-substituted porphyrins by 4-(3-N,N,N-trimethylammoniumpropoxy)phenyl and 4-(trifluoromethyl)phenyl groups

Caminos

Spesia

Durantini

2006

Photochem Photobiol Sci

120

127

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The photodynamic effect of novel cationic porphyrins, with different pattern of meso-substitution by 4-(3-N,N,N-trimethylammoniumpropoxy)phenyl (A) and 4-(trifluoromethyl)phenyl (B) groups, have been studied in both solution bearing photooxidizable substrates and in vitro on a typical Gram-negative bacterium Escherichia coli. In these sensitizers, the cationic groups are separated from the macrocycle ring by a propoxy spacer. Thus, the charges have a high mobility and a minimal influence on photophysical properties of the porphyrin. These compounds produce singlet molecular oxygen, O2(1Delta(g)), with quantum yields of approximately 0.41-0.53 in N,N-dimethylformamide. In methanol, the l-tryptophan photodecomposition increases with the number of cationic charges in the sensitizer. In vitro investigations show that cationic porphyrins are rapidly bound to E. coli cells in approximately 5 min. A higher binding was found for A3B3+ porphyrin, which is tightly bound to cells still after three washing steps. Photosensitized inactivation of E. coli cellular suspensions follows the order: A3B3+ > A44+>> ABAB2+ > AB3+. Under these conditions, a negligible effect was found for 5,10,15,20-tetra(4-sulfonatophenyl)porphyrin (TPPS4(4-)) that characterizes an anionic sensitizer. Also, the results obtained for these new cationic porphyrins were compared with those of 5,10,15,20-tetra(4-N,N,N-trimethylammonium phenyl)porphyrin (TTAP4+), which is a standard active sensitizer established to eradicate E. coli. The photodynamic activity of TTAP4+ is quite similar to that produced by A4(4+). Studies in an anoxic condition indicate that oxygen is necessary for the mechanism of action of photodynamic inactivation of bacteria. The higher photodynamic activity of A3B3+ was confirmed by growth delay experiments. Photodynamic inactivation capacities of these sensitizers were also evaluated in E. coli cells immobilized on agar surfaces. Under these conditions, A3B3+ porphyrin retains a high activity to inactivate localized bacterial cells. Therefore, tricationic porphyrin A3B3+ is an interesting sensitizer with potential applications in photodynamic inactivation of bacteria in liquid suspensions or on surfaces.

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Section: Spectroscopic Studiesmentioning

confidence: 99%

Photodynamic inactivation of Escherichia coli by novel meso-substituted porphyrins by 4-(3-N,N,N-trimethylammoniumpropoxy)phenyl and 4-(trifluoromethyl)phenyl groups

Caminos

Spesia

Durantini

2006

Photochem Photobiol Sci

120

127

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“…The redox potentials show that porphycenes, both as free bases or as metallo-complexes, are easier to reduce but more difficult to oxidize than their porphyrin counterparts. Porphycenes are indeed able to undergo type-I photooxidation processes [217].…”

Section: Non-radiative Decay Processesmentioning

confidence: 99%

Porphycenes: Facts and Prospects in Photodynamic Therapy of Cancer

Stockert¹,

Cañete²,

Juarranz³

et al. 2007

CMC

177

130

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The photodynamic process induces cell damage and death by the combined effect of a photosensitizer (PS), visible light, and molecular oxygen, which generate singlet oxygen ((1)O(2)) and other reactive oxygen species that are responsible for cytotoxicity. The most important application of this process with increasing biomedical interest is the photodynamic therapy (PDT) of cancer. In addition to hematoporphyrin-based drugs, 2nd generation PSs with better photochemical properties are now studied using cell cultures, experimental tumors and clinical trials. Porphycene is a structural isomer of porphyrin and constitutes an interesting new class of PS. Porphycene derivatives show higher absorption than porphyrins in the red spectral region (lambda > 600 nm, epsilon > 50000 M-(1)cm(-1)) owing to the lower molecular symmetry. Photophysical and photobiological properties of porphycenes make them excellent candidates as PSs, showing fast uptake and diverse subcellular localizations (mainly membranous organelles). Several tetraalkylporphycenes and the tetraphenyl derivative (TPPo) induce photodamage and cell death in vitro. Photodynamic treatments of cultured tumor cells with TPPo and its palladium(II) complex induce cytoskeletal changes, mitotic blockage, and dose-dependent apoptotic or necrotic cell death. Some pharmacokinetic and phototherapeutic studies on experimental tumors after intravenous or topical application of lipophilic alkyl-substituted porphycene derivatives are known. Taking into account all these features, porphycene PSs should be very useful for PDT of cancer and other biomedical applications.

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“…54 In addition, electron-transfer quenching of porphycene or phthalocyanine excited states by Trp has been postulated. 55, 56 Furthermore, the photosensitized oxidation of Trp was found to be more than two orders of magnitude more efficient via electron transfer than via O 2 ( 1 ∆ g ). 57 In our cases, the decomposition of both substrates is faster in air-saturated solutions.…”

Section: Photosensitized Decomposition Of Substratesmentioning

confidence: 99%

Photodynamic activity of monocationic and non-charged methoxyphenylporphyrin derivatives in homogeneous and biological media

Milanesio

Alvarez

Silber

et al. 2003

Photochem Photobiol Sci

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A novel 5-[4-(trimethylammonium)phenyl]-10,15,20-tris(2,4,6-trimethoxyphenyl)porphyrin iodide (2) has been synthesized. A positive charge was incorporated at a peripheral position to increase the amphiphilic character of the structure. The photodynamic effect of the cationic porphyrin 2 was compared with that of non-charged 5-(4-aminophenyl)-10,15,20-tris(2,4,6-trimethoxyphenyl)porphyrin (1), both in a homogeneous medium bearing photooxidizable substrates and in vitro on the Hep-2 human larynx carcinoma cell line. Absorption and fluorescence spectroscopic studies in different media show that 2 is essentially unaggregated in solution, and also in human cells. The singlet molecular oxygen, O2(1delta(g)), production was evaluated using 9,10-dimethylanthracene in N,N-dimethylformamide, yielding phi(delta) values of approximately 0.66 for both porphyrins. The addition of beta-carotene suppresses the O2(1delta(g))-mediated photooxidation. L-Tryptophan and guanosine 5'-monophosphate were used as biological substrate models. Porphyrin 2 sensitizes the decomposition of both compounds faster than does 1. In the biological medium, no dark cytotoxicity was observed, even though a high porphyrin concentration (10 microM) and a long incubation time (24 h) were employed. Cell treatments were performed with 5 microM of porphyrin for 24 h. Under these conditions, the uptake of porphyrin 2 into Hep-2 was about 3 times higher than that of 1. Cell survival after irradiation with visible light was dependent upon both the light exposure level and intracellular sensitizer concentration. Thus, a higher photocytotoxic effect was found for porphyrin 2 in comparison to 1. These results show that the amphiphilic monocationic porphyrin 2 could be a promising model for phototherapeutic agents with potential applications in tumor cell inactivation by photodynamic therapy.

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Tryptophan Quenching of Zinc‐Phthalocyanine and Porphycene Fluorescence in Micellar CTAC

Cited by 12 publications

References 43 publications

Photodynamic inactivation of Escherichia coli by novel meso-substituted porphyrins by 4-(3-N,N,N-trimethylammoniumpropoxy)phenyl and 4-(trifluoromethyl)phenyl groups

Photodynamic inactivation of Escherichia coli by novel meso-substituted porphyrins by 4-(3-N,N,N-trimethylammoniumpropoxy)phenyl and 4-(trifluoromethyl)phenyl groups

Porphycenes: Facts and Prospects in Photodynamic Therapy of Cancer

Photodynamic activity of monocationic and non-charged methoxyphenylporphyrin derivatives in homogeneous and biological media

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