Photosensitizing properties of chlorins in solution and in membrane-mimicking systems.
The photosensitizing properties of three chlorins, meso-tetra(3-hydroxyphenyl)chlorin (m-THPC), chlorin e6 (Ce6) and meso-tetraphenylchlorin substituted by two adjacent sulfonated groups (TPCS(2a)) are compared in solution and when incorporated in dioleoyl-sn-phosphatidylcholine (DOPC) liposomes. In solution, the three chlorins possess a similar efficacy to generate singlet oxygen (quantum yield approximately 0.65). The formation of conjugated dienes was used to determine their ability to induce the peroxidation of methyl linoleate as a target of singlet oxygen. In ethanol solution, the apparent quantum yield for this process is the same for the three chlorins and its value agrees with that expected from the known rates for the decay of singlet oxygen and its reaction with methyl linoleate. When incorporated in liposomes, the order of efficacy is m-THPC > TPCS(2a) > Ce6. This order is tentatively assigned to the relative embedment of the photosensitizer within the lipidic bilayer, TPCS(2a) and Ce6 being anchored by their negative chains nearer to the water-lipid interface. The photoinduced permeation of the lipidic bilayer by these chlorins was investigated by measuring the release of carboxyfluorescein entrapped into DOPC liposomes. The charged chlorins, in particular TPCS(2a), are the most efficient, a result discussed in relation with the technology of photochemical internalization, PCI.
Mojzisova
Halina
H
Laboratoire Acides Nucléiques et BioPhotonique (ANBioPhi), CNRS FRE 3207, 91030 Evry cedex, France.
Bonneau
Stéphanie
S
Maillard
Philippe
P
Berg
Kristian
K
Brault
Daniel
D
D032701:Biomimetics; D008041:Linoleic Acids / Q000378:metabolism; D008051:Lipid Bilayers / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects / Q000528:radiation effects; D008081:Liposomes / Q000737:chemistry* / Q000378:metabolism*; D010539:Permeability / Q000187:drug effects / Q000528:radiation effects; D010713:Phosphatidylcholines; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000494:pharmacology*; D026082:Singlet Oxygen / Q000737:chemistry; D012996:Solutions
D008041:Linoleic Acids; D008051:Lipid Bilayers; D008081:Liposomes; D010713:Phosphatidylcholines; D017319:Photosensitizing Agents; D012996:Solutions; D026082:Singlet Oxygen; C005575:methyl linoleate; C017251:1,2-oleoylphosphatidylcholine