# Engineering synthetic cells with intramembrane domains possessing distinct bilayer asymmetries

## TL;DR

The paper introduces a new method to create synthetic cells with membranes that mimic natural cell membranes by having asymmetric lipid distributions and phase-separated domains.

## Contribution

A novel inverted emulsion method is developed to produce synthetic cells with controlled membrane asymmetry and phase-separated domains.

## Key findings

- The synthetic cells displayed membrane curvature, budding, and division when asymmetric and phase-separated membranes were used.
- The method allows for the creation of biomimetic membranes with lipid compositions similar to natural cell membranes.
- Protein-lipid interaction and quenching assays confirmed the presence of lipid asymmetry in the synthetic cells.

## Abstract

Our understanding of how membrane asymmetry governs biological function is limited by the lack of techniques to produce model membranes which can reliably and accurately mimic cellular membrane asymmetry. Not only in terms of asymmetric lipid distribution, but also how that asymmetry can be confined to specific lateral locations across the membrane. Here we present an inverted emulsion method that can be used to produce synthetic cells with symmetric and asymmetric bilayers, as well as phase separation where the intermembrane domains possess distinct bilayer asymmetries. We assess the degree of lipid asymmetry using protein-lipid interaction and quenching assays. Surprisingly, the synthetic cells with asymmetric and phase separated membranes displayed pronounced curvature of the domains and resulted in membrane budding and division. Overall, this work develops biomimetic membranes with lipid compositions akin to natural biomembranes – an essential element in the development of functional synthetic cells.

Lipid bilayer asymmetry, phase separation, and encapsulation are long standing issues in the development of synthetic cells. Here the authors develop an inverted emulsion method that can produce synthetic cells with symmetric and asymmetric bilayers, as well as phase separation with domains possessing distinct bilayer asymmetries.