The Role of Membrane Fluidization in the Gel-Assisted Formation of Giant Polymersomes.

Adrienne C Greene,Ian M Henderson,Andrew Gomez,Walter F Paxton,George D Bachand,Virginia Vandelinder,Dariush Hinderberger

doi:10.1371/journal.pone.0158729

Adrienne C Greene, Ian M Henderson + Show 5 more

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https://doi.org/10.1371/journal.pone.0158729

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Abstract

Polymersomes are being widely explored as synthetic analogs of lipid vesicles based on their enhanced stability and potential uses in a wide variety of applications in (e.g., drug delivery, cell analogs, etc.). Controlled formation of giant polymersomes for use in membrane studies and cell mimetic systems, however, is currently limited by low-yield production methodologies. Here, we describe for the first time, how the size distribution of giant poly(ethylene glycol)-poly(butadiene) (PEO-PBD) polymersomes formed by gel-assisted rehydration may be controlled based on membrane fluidization. We first show that the average diameter and size distribution of PEO-PBD polymersomes may be readily increased by increasing the temperature of the rehydration solution. Further, we describe a correlative relationship between polymersome size and membrane fluidization through the addition of sucrose during rehydration, enabling the formation of PEO-PBD polymersomes with a range of diameters, including giant-sized vesicles (>100 μm). This correlative relationship suggests that sucrose may function as a small molecule fluidizer during rehydration, enhancing polymer diffusivity during formation and increasing polymersome size. Overall the ability to easily regulate the size of PEO-PBD polymersomes based on membrane fluidity, either through temperature or fluidizers, has broadly applicability in areas including targeted therapeutic delivery and synthetic biology.

Highlights

Giant unilamellar vesicles (GUVs) are biological membrane models created through the selfassembly of amphiphilic molecules[1]
We have shown that gel-assisted rehydration is a convenient method for producing cell-sized and considerably larger polymersomes from poly(ethylene glycol)-poly(butadiene) (PEO-PBD) block copolymers
In addition to the simple and robust nature of this technique, we describe the ability to modulate membrane fluidity of low molecular weight PEO-PBD polymersomes using temperature and small-molecule fluidizers during rehydration, resulting in an easy means of tuning vesicle size

Summary

Introduction

Giant unilamellar vesicles (GUVs) are biological membrane models created through the selfassembly of amphiphilic molecules[1]. While lipid GUVs are excellent mimics of bio-membrane systems, they have inherent limitations, including short shelf life and degradation from various environmental perturbations. To overcome these restrictions, the use of polymer vesicles, or polymersomes, is being widely explored as synthetic analogs of lipid vesicles. Nanotechnologies, an Office of Science User Facility operated for the U.S Department of Energy (DOE) Office of Science (user project number RA2015A0004). The specific roles of these authors are articulated in the ‘author contributions’ section. This does not alter the authors' adherence to PLOS ONE policies on sharing data and materials.

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