Spontaneous Expulsion of Giant Lipid Vesicles Induced by Laser Tweezers

TL;DR

This paper demonstrates that focused laser irradiation can induce a tense state in giant lipid vesicles, leading to the spontaneous expulsion of internal objects, explained by a model involving lipid ejection and osmotic effects.

Contribution

It introduces a novel laser-induced vesicle expulsion mechanism and provides a qualitative theoretical model explaining the process.

Findings

Laser irradiation creates a tense, pressurized vesicle state.

Internal objects can be expelled while nearly as large as the vesicle.

A lipid ejection and osmotic activity model explains the phenomena.

Abstract

Irradiation of a giant unilamellar lipid bilayer vesicle with a focused laser spot leads to a tense pressurized state which persists indefinitely after laser shutoff. If the vesicle contains another object it can then be gently and continuously expelled from the tense outer vesicle. Remarkably, the inner object can be almost as large as the parent vesicle; its volume is replaced during the exit process. We offer a qualitative theoretical model to explain these and related phenomena. The main hypothesis is that the laser trap pulls in lipid and ejects it in the form of submicron objects, whose osmotic activity then drives the expulsion.