title: Thermomechanical transitions of egg-ceramide monolayers.
abstract: Ceramides have unique biophysical properties. Their high melting temperature and their ability to form lateral domains have converted ceramides into the paradigm of rigid lipids. Here, using shear surface rheology of egg-ceramide Langmuir monolayers, a solid to fluid transition was evidenced as a vanishing shear rigidity at lower temperatures than the lipid melting temperature. Such a mechanical transition, which depends on the lipid lateral pressure, was found in a broad range temperature (40-50 °C). The solid to fluid transition was correlated to a LC to LC+LE phase transition, as confirmed by BAM experiments. Interestingly, together with the softening transition, a supercooling process compatible with a glassy behavior was found upon freezing. A new phase scenario is then depicted that broadens the mechanical behavior of natural ceramides. The phase diversity of ceramides might have important implications in their physiological roles.
authors.affiliation: †Departamento de Química Física I, Universidad Complutense, Ciudad Universitaria s/n, 28040 Madrid, Spain.|‡Instituto de Investigación Hospital 12 de Octubre (i+12), Avda. de Córdoba s/n, 28041 Madrid, Spain.
authors.forename: Elisa R
authors.initials: ER
authors.lastname: Catapano
authors.affiliation: §Grupo de Biofísica Molecular, Instituto Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain.
authors.forename: M P
authors.initials: MP
authors.lastname: Lillo
authors.affiliation: §Grupo de Biofísica Molecular, Instituto Química Física Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: García Rodríguez
authors.affiliation: †Departamento de Química Física I, Universidad Complutense, Ciudad Universitaria s/n, 28040 Madrid, Spain.|‡Instituto de Investigación Hospital 12 de Octubre (i+12), Avda. de Córdoba s/n, 28041 Madrid, Spain.
authors.forename: P
authors.initials: P
authors.lastname: Natale
authors.affiliation: ∥Laboratoire de Physique des Solides, Université Paris-Sud, Rue Nicolas Appert Bâtiment 510, 91405 Orsay, France.
authors.forename: D
authors.initials: D
authors.lastname: Langevin
authors.affiliation: †Departamento de Química Física I, Universidad Complutense, Ciudad Universitaria s/n, 28040 Madrid, Spain.|‡Instituto de Investigación Hospital 12 de Octubre (i+12), Avda. de Córdoba s/n, 28041 Madrid, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Monroy
authors.affiliation: †Departamento de Química Física I, Universidad Complutense, Ciudad Universitaria s/n, 28040 Madrid, Spain.|‡Instituto de Investigación Hospital 12 de Octubre (i+12), Avda. de Córdoba s/n, 28041 Madrid, Spain.
authors.forename: I
authors.initials: I
authors.lastname: López-Montero
mesh_terms: D002518:Ceramides / Q000737:chemistry*; D008051:Lipid Bilayers; D044367:Phase Transition; D013499:Surface Properties; D013696:Temperature
chemical_list: D002518:Ceramides; D008051:Lipid Bilayers