The influence of intracellular mTHPC concentration upon photobleaching dynamics

Stringer, Maurice; Cruse-Sawyer, Janet E.; Dyer, P. E.; Brown, Stanley B.

doi:10.1016/s1572-1000(05)00096-7

Cited by 17 publications

(11 citation statements)

References 5 publications

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“…Kasselouri et al (15) detected mono-, di-and tri-hydroxy-mTHPC as major photoproducts of mTHPC in ethanol-water medium. mTHPC photobleaching kinetics in spheroids and monolayer cultured cells were consistent with singlet oxygen-mediated mechanism (16) and depended on the dye intracellular concentration, fluence rate and oxygen partial pressure (17)(18)(19). Except for a single study where photobleaching of a liposomal mTHPC gel formulation was registered after its topical application in patients with skin carcinomas (20), this process has not been yet investigated for liposomal forms of mTHPC.…”

Section: Introductionmentioning

confidence: 93%

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Unusual Photoinduced Response of mTHPC Liposomal Formulation (Foslip)

Kachatkou

Sasnouski

Zorin

et al. 2009

Photochem & Photobiology

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Liposomal formulations of meso-tetra(hydroxyphenyl)chlorin (mTHPC) have already been proposed with the aim to optimize photodynamic therapy. Spectral modifications of these compounds upon irradiation have not yet been investigated. The objective of this study was to evaluate photobleaching properties of mTHPC encapsulated into dipalmitoylphosphatidylcholine (DPPC) liposomes, Foslip. Fluorescence measurements in DPPC liposomes with different DPPC:mTHPC ratios demonstrated a dramatic decrease in fluorescence anisotropy with increasing local mTHPC concentration, thus suggesting strong interactions between mTHPC molecules in lipid bulk medium. Exposure of Foslip suspensions to small light doses (<50 mJ/cm(2)) resulted in a substantial drop in fluorescence, which, however, was restored after addition to the sample of a non-ionic surfactant Triton X-100. We attributed this behavior to photoinduced fluorescence quenching. This effect depended strongly on the molar DPPC:mTHPC ratio and was revealed only for high local mTHPC concentrations. The results were interpreted supposing energy migration between closely located mTHPC molecules with its subsequent dissipation by the molecules of photoproduct acting as excitation energy traps. We further assessed the effect of photoinduced quenching in plasma protein solution. Relatively slow kinetics of photoinduced Foslip response during incubation in the presence of proteins was attributed to mTHPC redistribution from liposomal formulations to proteins. Therefore, changes in mTHPC distribution pattern in biological systems would be consistent with changes in photoinduced quenching and would provide valuable information on mTHPC interactions with a biological environment.

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Section: Introductionmentioning

confidence: 93%

“…Numerous studies have addressed the mechanism of mTHPC photobleaching in cells and cell-free systems (13)(14)(15)(16)(17)(18)(19). This process is oxygen dependent and is inhibited by singlet oxygen quenchers in serum-enriched solutions (13).…”

Section: Introductionmentioning

confidence: 99%

Unusual Photoinduced Response of mTHPC Liposomal Formulation (Foslip)

Kachatkou

Sasnouski

Zorin

et al. 2009

Photochem & Photobiology

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“…A clear relationship between 1 O 2 and bleaching rate was found (82) and the singlet oxygen concentration is inversely related to cell survival (83). Likewise, there is a correlation between drug concentration and rate of photobleaching for a fixed laser fluence rate (84).…”

Section: Chemistry and Development Of Temoporfinmentioning

confidence: 99%

Temoporfin (Foscan^®, 5,10,15,20‐Tetra(m‐hydroxyphenyl)chlorin)—A Second‐generation Photosensitizer^†,‡

Senge

Brandt

2011

Photochem & Photobiology

289

218

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“…The culture conditions and Foscan administration are the same as described in our previous reported studies [8][9].…”

Section: Methodsmentioning

confidence: 99%

In Vitro Studies of Photosensitizer fluorescence changes on singlet oxygen mediated photobleaching

Atif

2013

J. Phys.: Conf. Ser.

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Abstract:The effects of photosensitizer concentration on the singlet oxygen mediated photobleaching have been investigated in keratinocytes. Cells having different photosensitizers concentration were identified on the basis of the fluorescence signal amplitude and their fluorescence decay then studied to see if there was a correlation with concentration. The experimental results shows that the photobleaching was more rapid at the higher concentration as compared to lower concentration which mean that singlet oxygen plays a vital role in the rapid m-tetrahydroxyphenylchlorin (mTHPC) induced fluorescence photobleaching causing the sensitizer to degrade.

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The influence of intracellular mTHPC concentration upon photobleaching dynamics

Cited by 17 publications

References 5 publications

Unusual Photoinduced Response of mTHPC Liposomal Formulation (Foslip)

Unusual Photoinduced Response of mTHPC Liposomal Formulation (Foslip)

Temoporfin (Foscan^®, 5,10,15,20‐Tetra(m‐hydroxyphenyl)chlorin)—A Second‐generation Photosensitizer^†,‡

In Vitro Studies of Photosensitizer fluorescence changes on singlet oxygen mediated photobleaching

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The influence of intracellular mTHPC concentration upon photobleaching dynamics

Cited by 17 publications

References 5 publications

Unusual Photoinduced Response of mTHPC Liposomal Formulation (Foslip)

Unusual Photoinduced Response of mTHPC Liposomal Formulation (Foslip)

Temoporfin (Foscan®, 5,10,15,20‐Tetra(m‐hydroxyphenyl)chlorin)—A Second‐generation Photosensitizer†,‡

In Vitro Studies of Photosensitizer fluorescence changes on singlet oxygen mediated photobleaching

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Product

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Temoporfin (Foscan^®, 5,10,15,20‐Tetra(m‐hydroxyphenyl)chlorin)—A Second‐generation Photosensitizer^†,‡