Electric polarization and size of lipid nanotubes—an electric light scattering study

Abstract

Self-assembled lipid nanotubes (LNTs) could mimic the lipid bilayer of biological membranes and are widely used as substrates for proteins in the biotechnology. Since the protein-LNT binding depends strongly on the physicochemical properties of the LNT, we studied one of the important properties of the “naked” (not associated with protein) LNT—their electrical polarizability. The experiments were performed on galactosyl ceramide nanotubes suspension through electric light scattering method. The average values for the length of the LNT particles as well as the magnitude and type of their electrical polarizability are determinated. The analysis of the experimental results is performed on the basis of the comparison with the theory. The data were taken from experimental curves obtained from the variation of the electric light scattering effect with time, strength, and frequency of the applied electric field. The average values for the total electrical polarizability obtained from the electric light scattering effect in three independent ways give comparable results: 1.9, 1.4, and 0.9 × 10−29 F m2. The average value of the length of the galactosyl ceramide nanotubes was estimated to be about 0.95 μm, and the type of polarization was found to be “charge dependent“(electrokinetic) and of Maxwell-Wagner-O’Konski type. The method used here could be applicable to the most of the organic NTs.