Cp. Sotomayor et al., EFFECT OF THE INCORPORATION OF ALKANOLS UPON THE PROPERTIES OF DPPC VESICLES, DEPENDENCE WITH THE SOLUTE CONCENTRATION AND TOPOLOGY, Boletin de la Sociedad Chilena de Quimica, 41(1), 1996, pp. 93-97
Diphenylhexatriene (DPH) and three 9-antroyloxy derivatives of stearic
acid (AS) with the fluorescent moiety localized at different carbons
of the stearyl chain, has been employed as fluorescent probes to study
the changes produced in DPPC large unilamellar vesicles by the incorp
oration of several alkanols of different topology. From the modificati
on of the fluorescence anisotropy of these probes, the effect of the a
lkanol incorporation upon different parts of the bilayer are evaluated
. The biphasic behavior observed using AS probes is interpreted in ter
ms of crowding the interface followed by a disorganization of the cent
ral parts of the bilayer. Differences in the behavior of the AS probes
indicate that the fluidification of the central parts of the bilayer
is considerably larger than the disorganization of the bilayer borders
. The hypothesis that probes molecules create their own defects, where
the fluorophore rotation is rather unhindered, is raised in order to
explain !he existence of fluorescence anisotropy maxima of two of the
AS probes at relative low alkanol intravesicular concentrations.