Electroformation in a flow chamber with solution exchange as a means of preparation of flaccid giant vesicles

TL;DR

This paper evaluates a technique for preparing giant unilamellar vesicles (GUVs) in high ionic strength solutions, measuring membrane permeability, and proposing an alternative exchange mechanism, with applications to producing flaccid GUVs.

Contribution

It introduces modifications to an existing method for preparing flaccid GUVs and provides quantitative permeability data for POPC membranes.

Findings

Measured POPC membrane permeability for glycerol: (2.09±0.82) x 10^{-8} m/s.

Proposed an alternative mechanism for vesicle interior exchange.

Successfully applied the method to prepare flaccid GUVs.

Abstract

A recently described technique (Estes and Mayer, Biochim. Biophys. Acta 1712 (2005) 152--160) for the preparation of giant unilamellar vesicles (GUVs) in solutions with high ionic strength is examined. By observing a series of osmotic swellings followed by vesicle bursts upon a micropipette transfer of a single POPC GUV from a sucrose solution into an isoosmolar glycerol solution, a value for the permeability of POPC membrane for glycerol, P = (2.09+/-0.82) x 10^{-8} m/s, has been obtained. Based on this result, an alternative mechanism is proposed for the observed exchange of vesicle interior. With modifications, the method of Estes and Mayer is then applied to preparation of flaccid GUVs.