Local Mechanical Response of Lipid Membranes to Tilt Deformation

Using molecular dynamics, this study investigates the local elastic properties of transverse shear deformation of lipid membranes. The analysis demonstrates that transverse shear deformation induces anisotropy in the local stress profile of the lipid bilayer, a phenomenon attributed to the Poynting effect. By analyzing the relationship between transverse shear stress and the induced anisotropy, the local transverse shear modulus is determined. From the local transverse shear modulus, several integral elastic parameters can be derived, including the monolayer tilt modulus, tilt-curvature coupling modulus, and curvature-gradient modulus. The calculated tilt modulus values show good agreement with results from an independent analysis of lipid director fluctuations.