Phase state and surface topography of palmitoyl-ceramide monolayers

MARIA LAURA FANANI; BRUNO MAGGIO

ELSEVIER IRELAND LTD

Año: 2010 vol. 163 p. 594 - 594

p style="TEXT-ALIGN: justify; LINE-HEIGHT: 130%; TEXT-INDENT: 35.4pt; MARGIN: 0cm 0cm 0pt" class="MsoNormal">In cell biology (and in many biophysical) studies there is a natural tendency to consider ceramide as a highly condensed, solid-type lipid conferring rigidity and close packing to biomembranes. In the present work we advanced the understanding of the phase behavior of palmitoyl-ceramide restricted to a planar interface using Langmuir monolayers under strictly controlled and known surface packing conditions. Surface pressure-molecular area isotherms were complemented with molecular area-temperature isobars and with observations of the surface topography by Brewster Angle Microscopy. The results described herein indicate that palmitoyl-ceramide can exhibit expanded, as well as condensed phase states. Formation of three phases was found, depending on the surface pressure and temperature: a solid (1.80 nm thick),