The interaction of meso-tetraphenylporphyrin with phospholipid monolayers.
Chem Phys Lipids
; 134(2): 97-108, 2005 Apr.
Article
en En
| MEDLINE
| ID: mdl-15784228
In this article, we investigate the interaction of meso-tetraphenylporphyrin (TPP) with phospholipid monolayers. Pure TPP molecules form films at the air-water interface with large extension of aggregation, which is confirmed by UV-vis spectra of transferred monolayers. For mixed films of TPP with dipalmitoyl phosphatidyl choline (DPPC) or dipalmitoyl phosphatidyl glycerol (DPPG), on the other hand, aggregation is only significant at high surface pressures or high concentrations of TPP (above 0.1 molar ratio). This was observed via Brewster angle microscopy (BAM) for the Langmuir films and UV-vis spectroscopy for transferred layers onto solid substrates. TPP indeed causes the DPPC and DPPG monolayers to expand, especially at the liquid-expanded to liquid-condensed phase transition for DPPC. The effects from TPP cannot be explained using purely geometrical considerations, as the area per TPP molecule obtained from the isotherms is at least twice the expected value from the literature. Therefore, interaction between TPP and DPPC or DPPG should be cooperative, so that more phospholipid molecules are affected than just the first neighbors to a TPP molecule.
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01-internacional
Base de datos:
MEDLINE
Asunto principal:
Fosfolípidos
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Porfirinas
Idioma:
En
Revista:
Chem Phys Lipids
Año:
2005
Tipo del documento:
Article
País de afiliación:
Brasil
Pais de publicación:
Irlanda