title: Effect of liposomal confinement on photochemical properties of photosensitizers with varying hydrophilicity.
abstract: Preferential tumor localization and the aggregation state of photosensitizers (PSs) can depend on the hydrophilic/hydrophobic nature of the molecule and affect their phototoxicity. In this study, three PSs of different hydrophilicity are introduced in liposomes to understand the structure-photochemistry relationship of PSs in this cellular model system. Absorbance and fluorescence spectra of amphiphilic aluminum (III) phthalocyanine disulfonate chloride adjacent isomer (Al-2), hydrophilic aluminum (III) phthalocyanine chloride tetrasulfonic acid (Al-4), and lipophilic 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide (HPPH) are compared in a liposomal confined state with free PS in bulk solution. For fluorescence measurements, a broad range of concentrations of both bulk and liposomal confined PSs are examined to track the transition from monomers to dimers or higher order aggregates. Epifluorescence microscopy, absorbance, and fluorescence measurements all confirm different localization of the PSs in liposomes, depending on their hydrophilicity. In turn, the localization affects the aggregation of molecules inside the liposome cell model. Data obtained with such cellular models could be useful in optimizing the photochemical properties of photosensitizing drugs based on their structure-dependent interactions with cellular media and subcellular organelles.
authors.affiliation: INO (National Optics Institute), Department of Biophotonics, 2740 Einstein Street, Quebec G1P 4S4, Canada.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Noiseux
authors.forename: Ozzy
authors.initials: O
authors.lastname: Mermut
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Bouchard
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Cormier
authors.forename: Patrice
authors.initials: P
authors.lastname: Desroches
authors.forename: Michel
authors.initials: M
authors.lastname: Fortin
authors.forename: Pascal
authors.initials: P
authors.lastname: Gallant
authors.forename: Sébastien
authors.initials: S
authors.lastname: Leclair
authors.forename: Marcia L
authors.initials: ML
authors.lastname: Vernon
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Diamond
authors.forename: Michael S
authors.initials: MS
authors.lastname: Patterson
mesh_terms: D004337:Drug Carriers / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D008027:Light; D008081:Liposomes / Q000737:chemistry*; D008422:Materials Testing; D010777:Photochemistry / Q000379:methods; D017319:Photosensitizing Agents / Q000737:chemistry*; D012542:Scattering, Radiation
chemical_list: D004337:Drug Carriers; D008081:Liposomes; D017319:Photosensitizing Agents