Effect of liposomal confinement on photothermal and photo-oximetric fluorescence lifetimes of photosensitizers with varying hydrophilicity
| Autor: | Pascal Gallant, Patrice Desroches, Ozzy Mermut, Jean-Pierre Bouchard, Kevin R. Diamond, Jean-Francois Cormier, Michael S. Patterson, Marcia L. Vernon, Michel Fortin, Isabelle Noiseux, Sebastien Leclair |
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| Rok vydání: | 2008 |
| Předmět: |
Liposome
Drug Carriers Aqueous solution Hot Temperature Photosensitizing Agents Light Chemistry Photochemistry Kinetics Biomedical Engineering Photothermal therapy Fluorescence Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials Biomaterials Oxygen Liposomes Materials Testing Scattering Radiation Drug carrier Luminescence Deoxygenation Hydrophobic and Hydrophilic Interactions |
| Zdroj: | Journal of biomedical optics. 13(4) |
| ISSN: | 1083-3668 |
| Popis: | The time-resolved fluorescence of photosensitizers (PSs) of varying hydrophobicities, di-and tetrasulfonated Al phthalocyanines (Al-2 and Al-4), and Photochlor (HPPH), was investigated in liposomes used as cell-mimetic models. Using frequency-and time-domain apparatus, the fluorescence lifetime, tau(fluo), was compared for PSs free in aqueous solution and in a liposome-associated state at varied temperatures (25 to 78 degrees C) and oxygen concentrations (0-190 microM). The analysis of tau(fluo) revealed different decay behaviors for the free-solution and liposome-confined PSs, most significantly for the lipophilic HPPH. Hydrophilic PS drugs (Al-4, Al-2) were less affected by the liposomal confinement, depending on the relative hydrophilicity of the compound and the consequent localization in liposomes. Changes in the emission decay due to confinement were detected as differences in the lifetime between the bulk solution and the liposome-localized PS in response to heating and deoxygenation. Specifically, hydrophilic Al-4 produced an identical lifetime trend as a function of temperature both in solu and in a liposome-confined state. Hydrophobic HPPH exhibited a fundamental transformation in its fluorescence decay kinetics, transitioning from a multiexponential (in free solution) to single-exponential (in liposome) decay. Deoxygenation resulted in a ubiquitous tau(fluo) increase for all PSs in free solution, while the opposite, a tau(fluo) decrease, occurred in all liposomal PSs. |
| Databáze: | OpenAIRE |
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