Morphogenesis of membrane invaginations in spherical confinement

TL;DR

This paper investigates how fluid membranes deform within spherical confinement, revealing various invagination morphologies and their potential relevance to biological tissue and organelle development.

Contribution

It provides a detailed analysis of membrane shape transitions under confinement, highlighting new morphologies and mechanisms of invagination formation.

Findings

Single axisymmetric invagination occurs at slight excess area.

Self-contact leads to symmetry-breaking and ellipsoid-like shapes.

Multiple invaginations can form with increasing membrane area.

Abstract

We study the morphology of a fluid membrane in spherical confinement. When the area of the membrane is slightly larger than the area of the outer container, a single axisymmetric invagination is observed. For higher area, self-contact occurs: the invagination breaks symmetry and deforms into an ellipsoid-like shape connected to its outer part via a small slit. For even higher areas, a second invagination forms inside the original invagination. The folding patterns observed could constitute basic building blocks in the morphogenesis of biological tissues and organelles.