Potential-mediated interaction between dextran sulfate and negatively charged phospholipids films at air/water and liquid/liquid interfaces

C.I. CÁMARA; L.M. YUDI

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2013 vol. 113 p. 644 - 644

he effect of dextran sulfate (DS) on distearoyl phosphatidyl glycerol (DSPG) and distearoyl phospha-tidic acid (DSPA) films formed in the presence of Ca2Cl, LiCl or KCl as aqueous electrolytes, was analyzedby cyclic voltammetry, surface pressure-area and surface potential-area isotherms and Brewster anglemicroscopy. Experiments of cyclic voltammetry at the water/1,2-dichloroethane interface showed aninterfacial adsorption/desorption process in the presence of DSPG, or DSPA, DS and LiCl. It is suggested thatthis process could correspond to the formation of an interfacial complex DS?Li+?DSPG or DS?Li+?DSPA atpositive potentials with respect to the potential of zero charge (pzc) and its desorption from the interfacetowards the aqueous phase, by complex dissociation, at potentials below pzc. The voltammetric analy-sis of tetraethylammonium (TEA+) cation transfer, from the aqueous to the organic phase, evidenced ablocking effect of DSPG and DSPA films on that process, whose magnitude depen