INVESTIGADORES
BENEDINI Luciano Alejandro
congresos y reuniones científicas
Título:
Surface insertion of ascorbyl palmitate on phospholipid monolayers
Autor/es:
MARIA LAURA FANANI, MILAGRO MOTTOLA, NATALIA WILKE, LUCIANO BENEDINI, BRUNO MAGGIO
Lugar:
Tucumán
Reunión:
Congreso; XLI Reunión de la Sociadad Biofísica Argentina; 2012
Institución organizadora:
Sociedad Biofísica Argentina
Resumen:
Ascorbyl
palmitate (ASC16) is a molecule of potential pharmacological interest
due to its antioxidant properties and amphiphilic nature. In this work
we investigated its interaction with model lipid monolayers. ASC16 shows
an ionizable OH group (pKa 4.2) that leads to a charged surface upon
its insertion/adsorption to interface (1).
When ASC16 is added to the subfase of a phospholipid monolayer it
incorporates to the film showing a non-classical bimodal kinetics. From
the analysis of mixed Langmuir films and Brewster angle microscopy we
can conclude that the insertion kinetics of ASC16 leads to a
two-dimensional phase transition from liquid-expanded
(phospholipid-reach) film to a liquid-condensed phase enriched in the
amphiphilic drug. The latter phase is highly stable at the interface
reaching surface pressure values of ~65mN/m
and a theoretical cut off value of near 70mN/m. Subphase pH and ionic
strength are determinant of both the characteristics of ASC16 aggregates
in the bulk phase and the kinetic properties of ASC16 insertion to
phospholipid monolayers. Those effects are consequence of different
biophysical properties of the charged and neutral drug. Additionally, we
evaluated the insertion of ASC16 in phospholipid/cholesterol
monolayers. In this condition the kinetic of insertion shows a fast
hyperbolic increase. Preliminary results suggest that the presence of
cholesterol disrupt the ASC16-enriched liquid-condensed phase promoting a
rapid ASC16 insertion to the membrane.
References: (1). Benedini, L., Fanani, M. L., Maggio, B., Wilke, N., Messina, P., Palma, S., and Schulz, P. (2011) Langmuir 27, 10914-10919