Role of particle local curvature in cellular wrapping

TL;DR

This study investigates how the local curvature of particles influences cellular membrane wrapping during endocytosis, revealing that particle shape and orientation critically affect uptake efficiency and phase transitions.

Contribution

It introduces a phase diagram for membrane wrapping around elliptical particles, highlighting the impact of local curvature and orientation on cellular uptake mechanisms.

Findings

Wrapping depends on particle orientation and aspect ratio.

Three distinct wrapping regimes identified: unwrapped, partially wrapped, fully wrapped.

Analytical expressions confirm the influence of particle shape on phase transitions.

Abstract

Cellular uptake through the lipid membranes plays an important role in adsorbing nutrients and fighting infection and can be used for drug delivery and nanomedicine developments. Endocytosis is one of the known pathways of the cellular uptake which associate with elastic deformation of the membrane wrapping around the foreign particle. The deformability of the membrane itself is strongly regulated by the presence of a cortical cytoskeleton placed underneath the membrane. It has been shown that size, shape, and orientation of the particles influence on their entry into the cell. Here, we study the role of particle local curvature in the cellular uptake by investigating the wrapping of an elastic membrane around a long cylindrical object with an elliptical cross section. The membrane itself is adhered to a substrate mimicking the cytoskeleton. Membrane wrapping proceeds differently whether the initial contact occurs at the particle's highly curved tip (prolate) or along its long side (oblate). We obtain a wrapping phase diagram as a function of the membrane-cytoskeleton and the membrane-target adhesion energy, which includes three distinct regimes of engulfment(unwrapped, partially wrapped, and fully wrapped), separated by two phase transitions. We also provide analytical expressions for the boundary between the different regimes which confirm that the transitions strongly depend on the orientation and aspect ratio of the particle.