Overview of Theoretical and Computational Methods Applied to the Oxygen‐Organic Molecule Photosystem

Paterson, Martin J.; Christiansen, Ove; Jensen, Frank; Ogilby, Peter R.

doi:10.1562/2006-03-17-ir-851

Cited by 108 publications

(170 citation statements)

References 158 publications

(272 reference statements)

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“…The key point here is that, under the conditions in which we observe our intracellular Chlsensitized singlet oxygen signal (100% oxygen), we have no evidence of an intracellular population of 3 Chl with a lifetime longer than 4 µs. This is manifested in our singlet oxygen signals by the apparent lack of a rising component (i.e., k T > k rem in Eq.1.).…”

Section: Singlet Oxygen Production and Quenching By Nan 3 In Cells Wimentioning

confidence: 70%

“…These data point to a non-negligible k c [C] term, [13][14][15][16] as is indeed expected given that singlet oxygen can induce cell death. The quenching plots obtained using the NaN 3 equals the extracellular concentration in the incubating medium, the data in Figure 5 suggest that this intracellular quenching occurs at the diffusion-controlled limit. Moreover, in accordance with the calibration graph in Figure 5, the quenching rate constant of (1.0 ± 0.1) × 10 8 s -1 M -1 corresponds to an apparent intracellular viscosity of >25 mPa s. This conclusion is further strengthened by comparison with the results of singlet oxygen quenching by NaN 3 in…”

Section: When Incorporated Into Hela Cells Tmpyp Ultimately Tends Tomentioning

confidence: 85%

“…15,50 Chl phosphorescence can be readily detected at 800 nm from our HeLa cells (Figure 8). Upon exposing our cells to a nitrogen-saturated medium, intracellular 3 Chl decays with a lifetime of 8.8 ± 0.3 µs. This comparatively short lifetime can be attributed to incomplete deoxygenation of the cell.…”

Section: Singlet Oxygen Production and Quenching By Nan 3 In Cells Wimentioning

confidence: 99%

“…[1][2][3] It is wellestablished that singlet oxygen is an oxidizing/oxygenating agent for a wide range of organic molecules. 1,4 Production of sufficient quantities of singlet oxygen in a biological environment can perturb cellular processes, and can ultimately cause cell death via apoptosis or necrosis.…”

Section: Introductionmentioning

confidence: 99%

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Singlet Oxygen in a Cell: Spatially Dependent Lifetimes and Quenching Rate Constants

2008

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Singlet molecular oxygen, O 2 (a 1 ∆ g ), can be created in a single cell from ground state oxygen, O 2 (X 3 Σ g -), upon focused laser irradiation of an intracellular sensitizer. This cytotoxic species can subsequently be detected by its 1270 nm phosphorescence (a 1 ∆ g → X 3 Σ g -) with subcellular spatial resolution. The singlet oxygen lifetime determines its diffusion distance and, hence, the intracellular volume element in which singlet-oxygen-initiated perturbation of the cell occurs. In this study, the time-resolved phosphorescence of singlet oxygen produced by the sensitizers chlorin (Chl) and 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-21H,23H-porphine (TMPyP) was monitored. These molecules localize in different domains of a living cell. The data indicate that (i) the singlet oxygen lifetime and (ii) the rate constant for singlet oxygen quenching by added NaN 3 depend on whether Chl or TMPyP was the photosensitizer.These observations likely reflect differences in the chemical and physical constituency of a given subcellular domain (e.g., spatially-dependent oxygen and NaN 3 diffusion coefficients) and, as such, are evidence that singlet oxygen responds to the inherent heterogeneity of a cell.Thus, despite a relatively long intracellular lifetime, singlet oxygen does not diffuse a great distance from its site of production. This is a consequence of an apparent intracellular viscosity that is comparatively large.3

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Section: Singlet Oxygen Production and Quenching By Nan 3 In Cells Wimentioning

confidence: 70%

Section: When Incorporated Into Hela Cells Tmpyp Ultimately Tends Tomentioning

confidence: 85%

Section: Singlet Oxygen Production and Quenching By Nan 3 In Cells Wimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Singlet Oxygen in a Cell: Spatially Dependent Lifetimes and Quenching Rate Constants

2008

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“…The details of this energy transfer process are beyond the scope of this article but have been an area of active study. 16 Two approaches have been used to study PDT dynamics. First, a microscopic model takes into account diffusion of oxygen and photosensitizer from blood vessels and can determine the singlet oxygen concentration in cells microscopically.…”

Section: Iia Modeling the Dynamic Process Of Pdtmentioning

confidence: 99%

The role of photodynamic therapy (PDT) physics

2008

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Photodynamic therapy ͑PDT͒ is an emerging treatment modality that employs the photochemical interaction of three components: light, photosensitizer, and oxygen. Tremendous progress has been made in the last 2 decades in new technical development of all components as well as understanding of the biophysical mechanism of PDT. The authors will review the current state of art in PDT research, with an emphasis in PDT physics. They foresee a merge of current separate areas of research in light production and delivery, PDT dosimetry, multimodality imaging, new photosensitizer development, and PDT biology into interdisciplinary combination of two to three areas. Ultimately, they strongly believe that all these categories of research will be linked to develop an integrated model for real-time dosimetry and treatment planning based on biological response.

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Characterization of the Oxygen Binding Motif in a Ruthenium Water Oxidation Catalyst by Vibrational Spectroscopy

et al. 2016

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For homogeneous mononuclear ruthenium water oxidation catalysts, the Ru–O2 complex plays a crucial role in the rate determining step of the catalytic cycle, but the exact nature of this complex is unclear. Herein, the infrared spectra of the [Ru(tpy)(bpy)(O2)]2+ complex (tpy=2,2′:6′,2′′‐terpyridine; bpy=2,2′‐bipyridine) are presented. The complex [Ru(tpy)(bpy)(O2)]2+, formed by gas‐phase reaction of [Ru(tpy)(bpy)]2+ with molecular O2, was isolated by using mass spectrometry and was directly probed by cryogenic ion IR predissociation spectroscopy. Well‐resolved spectral features enable a clear identification of the O−O stretch using 18O2 substitution. The band frequency and intensity indicate that the O2 moiety binds to the Ru center in a side‐on, bidentate manner. Comparisons with DFT calculations highlight the shortcomings of the B3LYP functional in properly depicting the Ru–O2 interaction.

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Overview of Theoretical and Computational Methods Applied to the Oxygen‐Organic Molecule Photosystem

Cited by 108 publications

References 158 publications

Singlet Oxygen in a Cell: Spatially Dependent Lifetimes and Quenching Rate Constants

Singlet Oxygen in a Cell: Spatially Dependent Lifetimes and Quenching Rate Constants

The role of photodynamic therapy (PDT) physics

Characterization of the Oxygen Binding Motif in a Ruthenium Water Oxidation Catalyst by Vibrational Spectroscopy

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