Reflectance and topography of glycosphingolipid monolayers at the air-water interface.

ROSETTI, C. M.; RAFAEL GUSTAVO OLIVEIRA; MAGGIO, B.

LANGMUIR

American Chemical Society

Año: 2003 vol. 19 p. 377 - 377

0743-7463

n this paper we report the dynamic response of the lateral topography and reflectance of monolayers of glycosphingolipids under changes of surface pressure (ð) and composition. Epifluorescence and Brewster angle microscopy (BAM) observations have been carried out on pure monolayers formed with ceramide (Cer) and a series of glycosphingolipids (galactocerebroside, GM1 ganglioside, and asialo-GM1), and on mixed films formed with Cer and GM1. The curves of reflectance versus ð for films of pure components are very dependent on the type and length of the oligosaccharide chain in the polar headgroup and are in agreement with the phase state of the ð-area isotherms and with the overall molecular reorientation under compression shown by the variation of the perpendicular resultant dipole moments. In turn, the surface appearance of films formed with mixtures of GM1 and Cer is homogeneous as assessed by BAM, but epifluorescence microscopy reveals the coexistence of expanded and condensed phase