Hematoporphyrin-Derivative (HpD), a widely-used tumor-specific photosensitizer, is a complex mixture of porphyrins whose composition has yet to be clarified. This paper reports on the behaviour of HpD in saline. From a spectroscopic point of view, the fresh solution is characterized by two main absorption peaks, attributable to monomeric and dimeric forms. With aging, a new porphyrin species (NPS) appears. To define the NPS, absorption, excitation and emission spectra were measured in different conditions and time-resolved fluorescence measurements were also performed. This species exhibits an absorption/excitation peak at 405 nm, an emission peak at 575 nm and a fluorescence decay time of ∼3.5 ns. Its formation is strongly influenced by many environmental factors: in particular, gases diluted in the solution, temperature, pH and concentration. The presence of Oxygen and a pH value outside the 6–8 range may be considered inhibiting factors. The NPS seems to be quite important in the understanding of HpD tumor-specificity, since the presence of an emission band similar to the NPS one seems to be favoured in tumor cells as compared with normal cells.
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Titolo: | The time-dependent behaviour of Hematoporphyrin Derivative in saline: a study of the spectral modifications | |
Autori: | ||
Data di pubblicazione: | 1984 | |
Rivista: | ||
Abstract: | Hematoporphyrin-Derivative (HpD), a widely-used tumor-specific photosensitizer, is a complex mixture of porphyrins whose composition has yet to be clarified. This paper reports on the behaviour of HpD in saline. From a spectroscopic point of view, the fresh solution is characterized by two main absorption peaks, attributable to monomeric and dimeric forms. With aging, a new porphyrin species (NPS) appears. To define the NPS, absorption, excitation and emission spectra were measured in different conditions and time-resolved fluorescence measurements were also performed. This species exhibits an absorption/excitation peak at 405 nm, an emission peak at 575 nm and a fluorescence decay time of ∼3.5 ns. Its formation is strongly influenced by many environmental factors: in particular, gases diluted in the solution, temperature, pH and concentration. The presence of Oxygen and a pH value outside the 6–8 range may be considered inhibiting factors. The NPS seems to be quite important in the understanding of HpD tumor-specificity, since the presence of an emission band similar to the NPS one seems to be favoured in tumor cells as compared with normal cells. | |
Handle: | http://hdl.handle.net/11571/100191 | |
Appare nelle tipologie: | 1.1 Articolo in rivista |