# Membrane‐Mediated Force Transduction Drives Stick‐Slip Motion of Lipid Vesicles

## TL;DR

Researchers show how rotating a magnetic particle inside a lipid vesicle creates stick-slip motion, revealing how membranes convert internal forces into movement.

## Contribution

A minimal system is used to demonstrate stick-slip propulsion driven by membrane-mediated force transduction in lipid vesicles.

## Key findings

- Rotating a magnetic particle inside a lipid vesicle generates internal flows that induce stick-slip motion.
- Membrane elasticity, excess area, and phase coexistence modulate vesicle propulsion through stress dissipation and force transduction.
- Deformations and line tension influence particle deflection and membrane reorientation during motion.

## Abstract

How internal forces are transduced into motion through soft, fluid membranes remains a fundamental question in the study of active systems. This is investigated using a minimal system: a ferromagnetic particle encapsulated inside a lipid vesicle with controlled membrane composition and phase behavior. A rotating magnetic field drives particle rotation, generating internal flow. This flow propels the particle along the inner membrane leaflet and induces local membrane slip, with regions closer to the particle exhibiting faster motion relative to the substrate. When the particle approaches the vesicle bottom, this slip produces a shear gradient across the lubrication gap, resulting in vesicle propulsion through a stick‐slip cycle. Vesicle motion depends on membrane elasticity, excess area, and phase coexistence. Deformations and fluctuations dissipate stress, while line tension deflects the particle and reorients membrane structure. The results demonstrate how lipid membranes mediate force transduction and motion, offering new avenues for the bottom‐up design of soft, membrane‐based active systems.

A rotating magnetic field actuates a ferromagnetic particle inside a lipid vesicle, generating internal flows that induce stick‐slip propulsion near a surface. Membrane properties—elasticity, excess area, and phase behavior—modulate this motion by shaping stress dissipation and force transduction. The system reveals how soft membranes regulate active transport and inspire membrane‐based micromachine design.