Supported membranes on polyelectrolyte layers studied by X-ray reflectometry

Supported lipid membranes on polymer layers were investigated by X-ray reflectivity in aqueous environment using a microfluidic setup. Polyallylamine hydrochloride and poly(sodium 4-styrenesulfonate) were used for building up multilayer architectures with alternating charge distribution. First results from synchrotron reflectivity experiments demonstrate that such polyelectrolyte layers can act as aqueous spacers with almost negligible electron density contrast as compared to water. Lipid membranes on top of such polymer spacers are expected to show only minor structural denaturation. Thus this model system is proposed as a step towards decoupling lipid membranes from solid substrates. The accessibility to such biological systems using high-resolution X-ray reflectivity and the possibility to insert well-defined spacers with minimum contrast are highly competitive to established methods of neutron reflectivity.