Photochemical reactions in organized monolayer assemblies. 8. Environmental effects on photochemical reactions: contrasts in the photooxidation behavior of protoporphyrin IX in solution, monolayer films, organized monolayer assemblies, and micelles

Horsey, Barbara E.; Whitten, David G.

doi:10.1021/ja00472a046

Cited by 51 publications

(15 citation statements)

References 4 publications

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“…The photoproduct fluorescence spectra that we observe are very similar to those recorded in 5-ALA-treated tissues (10)(11)(12)17,18). These have been suggested by Whitten and coworkers (15,16) as chlorin products because they appear to have the red Q band feature typical of a chlorin-type photoproduct. Previous studies (10)(11)(12)17,18) have shown that it is difficult to identify the exact nature of the photoproduct.…”

Section: Two-photon Spectroscopysupporting

confidence: 86%

“…Protoporphyrin IX is the sensitizer generated in situ when a specimen or subject has been administered its metabolic precursor, 5-ALA (9). The photochemical behavior of PpIX has been extensively documented (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) and thus serves as an excellent test case for TPE-PDT. Furthermore, because the photochemical behavior of PpIX may depend on the mode of excitation, TPE studies may help to shed light on some of its photodynamic anomalies.…”

Section: Introductionmentioning

confidence: 99%

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Near-Infrared Two-Photon Excitation of Protoporphyrin IX: Photodynamics and Photoproduct Generation¶

Goyan

Cramb

2000

Photochemistry and Photobiology

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The spectroscopy and photochemistry of protoporphyrin IX in ethanol and in Triton X‐100 micelle solution have been examined using near‐infrared two‐photon excitation (TPE). TPE will allow photodynamic therapy with highly localized light dosage. We have determined that the photochemistry subsequent to TPE is very similar to that found for one‐photon excitation. Moreover, the photoproducts observed possess very intense TPE fluorescence spectra, which allows their detection at low relative concentrations.

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Section: Two-photon Spectroscopysupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Near-Infrared Two-Photon Excitation of Protoporphyrin IX: Photodynamics and Photoproduct Generation¶

Goyan

Cramb

2000

Photochemistry and Photobiology

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“…For the case of PpIX, this result is qualitatively consistent with a finding published by Krieg and Whitten (2), who concluded that the detailed mechanism of PpIX bleaching in erythrocyte ghosts involved reaction of 1 O 2 with an intermediate oxidizable amino acid. An oxygen dependence to the rate of Photofrin bleaching is consistent with results reported by Spikes (5), although the extent of the role of 1 O 2 was not clear in that study, which was performed using a variety of model environments in fluid solution.…”

Section: Introductionsupporting

confidence: 88%

Porphyrin Bleaching and PDT-induced Spectral Changes are Irradiance Dependent in ALA-sensitized Normal Rat Skin In Vivo¶

Finlay¹,

Conover²,

Hull³

et al. 2001

Photochem Photobiol

142

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Photobleaching kinetics of aminolevulinic acid-induced protoporphyrin IX (PpIX) were measured in the normal skin of rats in vivo using a technique in which fluorescence spectra were corrected for the effects of tissue optical properties in the emission spectral window through division by reflectance spectra acquired in the same geometry and wavelength interval and for changes in excitation wavelength optical properties using diffuse reflectance measured at the excitation wavelength. Loss of PpIX fluorescence was monitored during photodynamic therapy (PDT) performed using 514 nm irradiation. Bleaching in response to irradiances of 1, 5 and 100 mW cm-2 was evaluated. The results demonstrate an irradiance dependence to the rate of photobleaching vs irradiation fluence, with the lowest irradiance leading to the most efficient loss of fluorescence. The kinetics for the accumulation of the primary fluorescent photoproduct of PpIX also exhibit an irradiance dependence, with greater peak accumulation at higher irradiance. These findings are consistent with a predominantly oxygen-dependent photobleaching reaction mechanism in vivo, and they provide spectroscopic evidence that PDT delivered at low irradiance deposits greater photodynamic dose for a given irradiation fluence. We also observed an irradiance dependence to the appearance of a fluorescence emission peak near 620 nm, consistent with accumulation of uroporphyrin/coproporphyrin in response to mitochondrial damage.

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“…Photoconversion of PpIX into two chlorin-type hydroxyaldehyde isomers called 'photoprotoporphyrin' has been documented (9,19). Several porphyrin-type formyl derivatives are formed during phototransformation of PpIX (19,20). The photophysical properties of Ppp and its dimethyl ester in organic solutions and biological environments has been investigated by several groups (16,17,(21)(22)(23)(24).…”

Section: Discussionmentioning

confidence: 99%

“…The environment of PpIX is of crucial importance for the photobleaching process (1,16,19,20,25,26). In organic solvents (methylene chloride, dimethylacetamide, acetone) the predominant photoproduct is the hydroxyaldehyde chlorin.…”

Section: Discussionmentioning

confidence: 99%

Phototransformations of 5-Aminolevulinic Acid-induced Protoporphyrin IX in vitro: A Spectroscopic Study¶

Bagdonas

Iani

et al. 2007

Photochemistry and Photobiology

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Human adenocarcinoma cells of the line WiDr were incubated with 5-aminolevulinic acid to induce protoporphyrin IX (PpIX) and then exposed to laser light of wavelength 635 nm. The PpIX fluorescence decreased with increasing exposure. The decay rate was slightly dependent on the initial PpIX concentration. The PpIX fluorescence was halved by a fluence of about 40 J/cm 2 . Several fluorescing photoproducts were formed. The main one, supposedly the chlorin-type photoprotoporphyrin (Ppp), had a fluorescence excitation spectrum stretching out to about 680 nm with a maximum at around 668 nm. The formation kinetics of this product was dependent on the initial PpIX concentration. Moreover, it was selectively bleached by exposure to light at 670 nm. A photoproduct with an emission maximum at 652 nm, different from Ppp, remained after this exposure. Traces of a photoproduct(s) with fluorescence emission slightly blueshifted compared with that of PpIX, supposedly watersoluble porphyrins, were also detected after light exposure. MATERIALS AND METHODSCell line. WiDr cells, derived from a primary human adenocarcinoma of the rectosigmoid colon, were used (a doubling period about

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Photochemical reactions in organized monolayer assemblies. 8. Environmental effects on photochemical reactions: contrasts in the photooxidation behavior of protoporphyrin IX in solution, monolayer films, organized monolayer assemblies, and micelles

Abstract: Die Photooxidation der Ester (I) des Protoporphyrins IX ergibt hauptsächlich die Hydroxyaldehyde (II) und die Dialdehyde (III).

Cited by 51 publications

References 4 publications

Near-Infrared Two-Photon Excitation of Protoporphyrin IX: Photodynamics and Photoproduct Generation¶

Near-Infrared Two-Photon Excitation of Protoporphyrin IX: Photodynamics and Photoproduct Generation¶

Porphyrin Bleaching and PDT-induced Spectral Changes are Irradiance Dependent in ALA-sensitized Normal Rat Skin In Vivo¶

Phototransformations of 5-Aminolevulinic Acid-induced Protoporphyrin IX in vitro: A Spectroscopic Study¶

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