Electrochemical behaviour of polyelectrolytes, magnetic nanoparticles and self-assembled molecules at liquid/liquid interfaces

CANDELARIA CÁMARA; JULIETA SOLEDAD RIVA; ANA VALERIA JUÁREZ; LIDIA MABEL YUDI

Congreso; 13a Conferencia Latinoamericana de Físico-Química Orgánica 13th Latin American Conference on Physical Organic Chemistry.; 2015

Numerous methods have been used to explore the structure of biomembranes and to associate its 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 biomembranes 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 interfaces formed by two immiscible liquids (water / organic solvent) [3]. The presence of polyelectrolytes associated to these monolayers provide additional information for modeling various membrane processes [4,5]. The possibility of polarizing the liquid/ liquid interfaces, using electrochemical methods applied to four electrodes systems, gives to these models an additional interest based in the importance of the electric potential in biomembranes. In this work we present a comparison of the interfacial behavior and the transfer mechanism of cationic polyelectrolytes: chitosan, polyquaternium-4 (PQ4, Celquat® L200), diethylaminoethyl dextran, polyquaternium-10 (PQ10, Celquat® SC230), and aminoacrilmetacrilato copolymer (Eudragit E100) and the results are correlated with the chemical structures. Also, we compare the effect of chitosan and dextran sulphate on the permeability and the compactness of a distearoilfosfatidilglycerol film adsorbed at liquid / liquid or liquid / air interfaces . The importance of this study is based, firstly, on the extensive use of these polymers in pharmaceutical preparations for topical use, and secondly, in the similarity between dextran and glycosaminoglycans (GAGs) which are one of the major components of the extracellular matrix of many tissues and cell surface.On another hand, the the electrochemical behaviour of cobalt (Co) and cobalt-boron (CoxB) magnetic nanoparticles (NPs) at a bare liquid/liquid interface and at a phospholipid monolayer adsorbed on these interfaces is also presented. The growing interest in ferromagnetic nanoparticles is largely motivated to their wide applications in biomedicine and biotechnology such as their use in magnetic resonance imaging, drug delivery and hyperthermia cancer therapies, all of them involving interactions between these nanoparticles and biomolecules components of biomembranes. References 1. B. Maggio, Prog. Biophys. Molec. Biol., 62 (1994) 55. 2. J.F. Liljeblad, V. Bulone, M. Rutland, C.M. Johnson, J. Phys. Chem. C, 115 (2011) 10617. 3. M.V. ColquiQuiroga, L.M.A. Monzón and L.M. Yudi,Electrochim. Acta 56 (2011) 7022. 4. C.I. Cámara and L.M. Yudi,Electrochim. Acta 113 (2013) 644. 5. J.S. Riva, D.M. Beltramo and L.M. Yudi,Electrochim. Acta 115 (2014) 370.