title: Porphyrin-phospholipid interaction and ring metallation depending on the phospholipid polar head type.
abstract: The interaction between a hydrophobically modified 5,10,15,20-tetrakis(4-N-tetradecyl-pyridyl) porphyrin and three phospholipids: two negatively charged, DMPA (the sodium salt of dimyristoyl-sn-glycero-phosphatidyl acid) and DMPG (the sodium salt of 1,2-dimyristoyl-sn-glycero-3-[phospho-rac-(1-glycerol)]) and a zwitterionic DMPC (dimyristoyl-sn-glycero-phosphatidylcholine), were studied by means of surface pressure isotherms and spectroscopic methods. The interaction results in partial or total metallation of the porphyrin with zinc ions in the presence of negatively charged phospholipids, as attested by UV-vis and luminescence spectroscopy of the transferred films. In the presence of the zwitterionic phospholipid no insertion of zinc ion in the porphyrin ring is detected. These results are relevant for the understanding of photosensitizer-lipid-carrier binding for use in photodynamic therapy.
authors.affiliation: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo 14040-901, Brazil. anapr@usp.br
authors.forename: Ana P
authors.initials: AP
authors.lastname: Ramos
authors.forename: Christiane
authors.initials: C
authors.lastname: Pavani
authors.forename: Yassuko
authors.initials: Y
authors.lastname: Iamamoto
authors.forename: Maria E D
authors.initials: ME
authors.lastname: Zaniquelli
mesh_terms: D007477:Ions; D008856:Microscopy, Fluorescence; D008956:Models, Chemical; D015394:Molecular Structure; D010743:Phospholipids / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D013499:Surface Properties; D015032:Zinc / Q000737:chemistry*
chemical_list: D007477:Ions; D010743:Phospholipids; D011166:Porphyrins; D015032:Zinc