Interaction of Semiflexible Filamentous Virus Particles with Freestanding Lipid Membranes

Abstract

Understanding of the mechanisms of interaction of macromolecules and colloidal particles with lipid membranes is far from complete, and the questions related to role of local perturbation of the membrane properties in these interactions are still largely unsolved. Previously, we have found [1] that interaction of DNA molecules with strongly charged freestanding cationic lipid bilayers [2] leads to an unexpected phenomenon of membrane-mediated coil-globule transition of membrane-absorbed DNA macromolecules. To elucidate the effect of the persistence length in these phenomena, we study the behavior of much stiffer semiflexible fd virus particles (persistence length ∼2.2 μm) electrostatically adsorbed on freestanding cationic lipid membranes. At low membrane charge densities, membrane-adsorbed fd virus particles behave as semiflexible filaments in 2D. On the other hand, we find that membrane-driven interactions at higher membrane charge densities are strong enough to induce the membrane-mediated coil-globule transition of the relatively stiff fd virus particles, which agrees with the recent theoretical predictions [3]. Further, for fd virus particles adsorbed at higher surface densities on weakly charged membranes we observe a new unexpected phenomenon of membrane-driven self-organization of the filamentous virus particles into long linear chain aggregates. [1] C. Herold, P. Schwille, and E. P. Petrov, Phys. Rev. Lett.104 (2010) 148102. [2] C. Herold, G. Chwastek, P. Schwille, and E. P. Petrov, Langmuir28 (2012) 5518. [3] A. G. Cherstvy and E. P. Petrov (2013) submitted.