Grazing-incidence X-ray scattering studies of lipid membranes at air/water interface: DPPC and Myelin

GASPERINI, ANTONIO M.; PUENTES-MARTINEZ XIMENA; RAFAEL GUSTAVO OLIVEIRA; CAVALCANTI, LEIDE PASOS

Rio de Janeiro

Encuentro; XIV Encontro da Sociedade Brasileira de Pesquisa em Materiais (SBPMat); 2015

Sociedade Brasileira de Pesquisa em Materiais

Thin and ultrathin films in liquid surfaces and interfaces have been intensively studied in different domains such as pharmaceutics, electronics, and food industry. These materials represent a model case to study the dynamical and structural properties of 2D confined soft matter. A very interesting class of ultrathin films is given by the Langmuir monolayers, which are monomolecular layers of amphiphilic molecules spread on air/water interfaces, since they can represent a model for biological systems. Langmuir monolayers formed by myelin lipids or full myelin membranes offer advantageous features to approach the exploration of the surface properties of a complex lipid-protein interface since they contain most of the components of natural membranes (1). Surface-sensitive synchrotron-based X-ray scattering techniques such as grazing-incidence diffraction (GID) and scattering (GISAXS/GIXOS) are powerful tools for investigating the molecular structure of organic films on liquid surfaces due to the penetrating properties of the X-rays and the ability to couple structural and dynamical properties of interfaces with nanoscale resolution (2). We present in this work the first results of a surface-sensitive X-ray scattering experiment performed at the Brazilian synchrotron (LNLS), XRD-2 beamline (3). We used this technique to study Langmuir monolayers formed by myelin lipids and full myelin membranes as a function of the monolayer surface pressure. The new experiment opens new possibilities for the soft condensed matter community in Brazil. The structural study as a function of the change of preparation conditions and thermodynamical parameters make this kind of experiment ideal for many technological and industrial applications.AAMG, RGO and LCP acknowledge grants from FAPESP.1Rosetti, C. et al. BBA - Biomemb.(2008) 1778, 1665;2Dai, Y. et al. J. Appl. Phys. (2011) 110, 102213;3Vieira, C. et al. J. Synch. Rad. (2015) 22, 859;