Self-spreading Lipid Bilayer at Ordered Metallic Nano-gap: Control and Application for Molecular Separation

Abstract

The self-spreading behavior of lipid bilayer was investigated using hydrophilic substrates with and without periodic array of metal nano-gaps. The self-spreading dynamics of the substrate without the architectures in electrolyte solution was quantitatively explained by the extended DLVO theory considering the van der Waals, electrostatic double layer, and hydration energies. Present findings suggest a possibility of controling the self-spreading dynamics by tuning the electrolyte concentration or substrate charge density. Furthermore, we demonstrated that the self-spreading dynamics was significantly affected due to the presence of nano-gaps. In addition to the change in the self-spreading dynamics, distribution of dye-labelled molecule doped in the self-spreading bilayer has also been changed. Both were strongly dependent on the gap width, i.e., narrower gap led to more pronounced effect on both the molecular distribution and the spreading dynamics. These phenomena have been attributable to the local compression induced during passing through the nano-gap.