Quantification and a Molecular Dynamics Study of Viral Membrane Lipids through Plasmon Coupling Microscopy

Abstract

Phosphatidylserine (PS) and monosialotetrahexosylganglioside (G_M1) are examples of two host-derived lipids in the membrane of enveloped virus particles that are known to contribute to virus attachment, uptake, and ultimately dissemination. A quantitative characterization of their contribution to the functionality of the virus requires information about their relative concentrations in the viral membrane. Here, a gold nanoparticle (NP) binding assay for probing relative PS and G_M1 lipid concentrations in the outer leaflet of different HIV-1 and Ebola virus-like particles (VLPs) using sample sizes of less than 3×10^6 particles is introduced. The assay evaluates both scattering intensity and resonance wavelength and determines relative NP densities through plasmon coupling as a measure for the target lipid concentrations in the NP-labeled VLP membrane. In addition, the mechanical properties of the viral membrane have been found to be contributing to the efficient reproduction cycle of the virus. Membrane fluidity which is a function of temperature and membrane composition is one of the crucial factors in viral activity. We have used temporally-resolved microscopy on silver NPs to track these molecular dynamics.