Variation in the fluorescence decay properties of haematoporphyrin derivative during its conversion to photoproducts

König, Karsten; Wabnitz, Heidrun; Dietel, W.

doi:10.1016/1011-1344(90)85192-y

Cited by 43 publications

(30 citation statements)

References 10 publications

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“…Nevertheless, these events yield similar emission spectra and cannot be detected using steady-state measurement. Therefore, additional contrast based on time-domain parameters may help distinguish these changes, and reveal the drug-molecular interactions for further correlation with treatment efficacy [31,45]. Note that TRF measurements of photosensitizers could be performed with the same wavelength used for treatment, providing convenience for treatment monitoring.…”

Section: The Potential Role Of Time-resolved Fluorescence (Trf) For Pmentioning

confidence: 99%

“…TRF studies relevant to different PDT photosensitizers have been reported by several research groups in the past decades [31,43,45,[70][71][72][73][74][75][76]. FDA-approved PDT photosensitizers include Photofrin ® , 5-aminolevulinic acid-induced protoporphyrin IX (ALA-PpIX), and verteporphyrin, Other photosensitizing agents in research stage, such as mTHPC (m-tetrahydroxyphenylchlorin, Foscan ® ), phthalocyanine (Pc) compounds, and chlorin-based compounds (i.e., HPPH), also showed promising results in terms of their singlet oxygen yield and more red-shifted absorption bands [77].…”

Section: Time-resolved Studies Of Pdt Photosensitizers In Solution Anmentioning

confidence: 99%

“…How these factors affect lifetime measurements of the photosensitizers will be further discussed. [43] 10 ns (Organic solution) [70] 5.5 ns (Mitochondria, MLL) [70] 13.3 ns (Monomer, mitochondria) [70] 13.6 ns (Monomer, mitochondria) [45] 8.5 ns (Aggregates, mitochondria) [45] 8.0 ns (Aggregates, mitochondria) [78] 4.8 ns (Cell membrane) [78] 1.0 ns (Aggregates, mouse model) [31] 13 ns (Monomers, mouse model) [31] 5 µg/mL 0.06-6 µg/mL 7.6 ns (liposome confined) [74] 6.4 ns (tissue phantom) [75] 4.3 ns (mouse tumor, before PDT) [75] 5.0 ns (mouse tumor, after PDT) [75] …”

Section: Time-resolved Studies Of Pdt Photosensitizers In Solution Anmentioning

confidence: 99%

“…The effective dosage is eventually altered by additional biological factors such as different drug uptake [22][23][24], various tissue optical properties [25], changes in vasculature and perfusion [26,27], and inconsistencies in tissue oxygenation [28], as well as unexpected photophysical and photochemical changes of photosensitizers [29][30][31]. The schematics of the three main dose factors are illustrated in Figure 1a, and the interdependencies of dose factors [32] are summarized in Table 1.…”

Section: Limitation Factors In Pdt Dosimetrymentioning

confidence: 99%

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Time-Resolved Fluorescence in Photodynamic Therapy

et al. 2014

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Photodynamic therapy (PDT) has been used clinically for treating various diseases including malignant tumors. The main advantages of PDT over traditional cancer treatments are attributed to the localized effects of the photochemical reactions by selective illumination, which then generate reactive oxygen species and singlet oxygen molecules that lead to cell death. To date, over-or under-treatment still remains one of the major challenges in PDT due to the lack of robust real-time dose monitoring techniques. Time-resolved fluorescence (TRF) provides fluorescence lifetime profiles of the targeted fluorophores. It has been demonstrated that TRF offers supplementary information in drug-molecular interactions and cell responses compared to steady-state intensity acquisition. Moreover, fluorescence lifetime itself is independent of the light path; thus it overcomes the artifacts given by diffused light propagation and detection geometries. TRF in PDT is an emerging approach, and relevant studies to date are scattered. Therefore, this review mainly focuses on summarizing up-to-date TRF studies in PDT, and the effects of PDT dosimetric factors on the measured TRF parameters. From there, potential gaps for clinical translation are also discussed. OPEN ACCESSPhotonics 2014, 1 531

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Section: The Potential Role Of Time-resolved Fluorescence (Trf) For Pmentioning

confidence: 99%

Section: Time-resolved Studies Of Pdt Photosensitizers In Solution Anmentioning

confidence: 99%

Section: Time-resolved Studies Of Pdt Photosensitizers In Solution Anmentioning

confidence: 99%

Section: Limitation Factors In Pdt Dosimetrymentioning

confidence: 99%

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Time-Resolved Fluorescence in Photodynamic Therapy

et al. 2014

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“…After confirming the LED source which most effectively caused photodegradation, the photobleaching experiments were repeated with the addition of sodium azide (NaN 3 ) to the solution. Sodium azide is a known singlet oxygen quencher and tends to decrease the time of permanence of singlet oxygen in the solution [30]. Singlet oxygen is responsible for the Type-II photodynamic effect, although it is believed that such effect may also be caused by the presence of oxidative free radicals (Type-I mechanism) [31,32].…”

Section: Methodsmentioning

confidence: 99%

Validation of Photodynamic Action via Photobleaching of a New Curcumin-Based Composite with Enhanced Water Solubility

et al. 2014

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Motivated by the photochemical and photophysical properties of curcumin-based composites, the characteristics of a new curcumin-based water-soluble salt were investigated via absorption and fluorescence spectroscopy. Photobleaching was investigated using a set of LEDs in three different wavelengths (405 nm, 450 nm and 470 nm) to illuminate an aqueous solution of curcumin, evaluating its degradation for five different exposure times (0, 5, 15, 45 and 105 minutes). The results were compared with equivalent measurements of dark degradation and illumination in the presence of a singletoxygen quencher. Three solution concentrations (50, 100 and 150 μg/ml) were studied. To measure the fluorescence, it was used low power 405 nm excitation laser source. Time dependent photodegradation of curcumin was observed, as compared to the natural degradation of samples maintained on a dark environment. Two main absorption peaks were detected and their relation responded to both concentration and wavelength of the illumination source. A spectral correlation between absorption of curcumin and the emission bands of the sources showed an optimal spectral overlap for the 450 nm LED. For this source, photobleaching showed a less intense degradation on the presence of singlet oxygen quencher. This last result confirmed singlet oxygen production in vitro, indicating a strong potential of this composite to be used as a bluelight-activated photosensitizer.

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Multi-colour fluorescence imaging in connection with photodynamic therapy of δ-amino levulinic acid (ALA) sensitised skin malignancies

et al. 1995

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A system for multi-colour fluorescence imaging of tissue is described. The instrument is mainly developed for tissue diagnostics to identify and localise malignant tumours, but might also be useful for real-time monitoring of the therapeutic dose delivered during photodynamic therapy. In vivo examples from various malignant skin lesions following topical δ-amino levulinic acid (ALA) administration are presented. The diagnostic system utilises both characteristics of a fluorescent tumour marker, such as a porphyrin containing substance, and the native tissue autofluorescence to characterise the tissue. A dimensionless function of three or four simultaneously recorded fluorescence intensities is formed and an optimum-contrast image is calculated pixel-by-pixel.

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Variation in the fluorescence decay properties of haematoporphyrin derivative during its conversion to photoproducts

Cited by 43 publications

References 10 publications

Time-Resolved Fluorescence in Photodynamic Therapy

Time-Resolved Fluorescence in Photodynamic Therapy

Validation of Photodynamic Action via Photobleaching of a New Curcumin-Based Composite with Enhanced Water Solubility

Multi-colour fluorescence imaging in connection with photodynamic therapy of δ-amino levulinic acid (ALA) sensitised skin malignancies

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