?Self?assembled films of polyelectrolytes and phospholipids at liquid/liquid interfaces?.

CANDELARIA I. CÁMARA; JULIETA S. RIVA; NATALIA WILKE; ANA VALERIA JUAREZ; LIDIA MABEL YUDI

Castle Tře?ť

Congreso; 48th Heyrovský Discussion, Progress in electrochemistry at liquid ? liquid interfaces and liquid membranes.; 2015

Heyrovsky Institute

Numerous methods have been used to explore the structure of bio-membranes and to associate their properties and environmental conditions with the intermolecular organization and, in some cases, with the function of membranes. Due to the difficulties of carrying out these studies in vivo, several simple models of artificial membranes, composed of proteins and lipids, have been developed. These studies confirm and extend the concept of bio-membranes as dynamic structures and emphasize the difficulty and importance of defining the precise characteristics of multimolecular arrangement used. In recent decades much of the information has been obtained from the use of lipid monolayers adsorbed at the air-water interface [1] or deposited on different solids by Langmuir-Blodgett method [2] as well as at liquid /liquid interfaces [3]. The presence of polyelectrolytes associated to these monolayers provide additional information for modelling various membrane processes [4,5]. In this work we present different relevant aspects related to the study of self-assembled molecules adsorbed at liquid/liquid interfaces. First, we describe the interfacial behaviour of phospholipid monolayers generated by simple injection of these molecules at the interface or by the Langmuir-Blodgett methodology. Secondly, we present a comparison of the interfacial behaviour and transfer mechanism of several cationic polyelectrolytes, including chitosan (CHI), polyquaternium-4 (PQ4, Celquat® L200) [6], diethylaminoethyl dextran (DEAE-D), polyquaternium-10 (PQ10, Celquat® SC230), and aminoacrylmethacrylate copolymer (Eudragit® E100) [5], correlating the results with the differences in their chemical structure. Finally, we compare the effect of cationic (CHI) and anionic (dextran sulphate, DS) polyelectrolytes on the permeability and the compactness of a distearoyl phosphatidyl glycerol (DSPG) film adsorbed at liquid/liquid or air/water interfaces [7,4]. The importance of these studies is based not only on the wide application of both polymers in pharmaceutical preparations for topical use but also in the similarity between DS and glycosaminoglycans (GAGs), which are one of the main components of the extracellular matrix of many tissues and can also be found inside or on the surface of cells.