Large and Giant Unilamellar Vesicle(s) Obtained by Self-Assembly of Poly(dimethylsiloxane)-b-poly(ethylene oxide) Diblock Copolymers, Membrane Properties and Preliminary Investigation of their Ability to Form Hybrid Polymer/Lipid Vesicles.

Martin Fauquignon,Marc Schmutz,Annie Brûlet,Stéphane Carlotti,Jean-François Le Meins,Emmanuel Ibarboure

doi:10.3390/polym11122013

Abstract

In the emerging field of hybrid polymer/lipid vesicles, relatively few copolymers have been evaluated regarding their ability to form these structures and the resulting membrane properties have been scarcely studied. Here, we present the synthesis and self-assembly in solution of poly(dimethylsiloxane)-block-poly(ethylene oxide) diblock copolymers (PDMS-b-PEO). A library of different PDMS-b-PEO diblock copolymers was synthesized using ring-opening polymerization of hexamethylcyclotrisiloxane (D3) and further coupling with PEO chains via click chemistry. Self-assembly of the copolymers in water was studied using Dynamic Light Scattering (DLS), Static Light Scattering (SLS), Small Angle Neutron Scattering (SANS), and Cryo-Transmission Electron Microscopy (Cryo-TEM). Giant polymersomes obtained by electroformation present high toughness compared to those obtained from triblock copolymer in previous studies, for similar membrane thickness. Interestingly, these copolymers can be associated to phospholipids to form Giant Hybrid Unilamellar Vesicles (GHUV); preliminary investigations of their mechanical properties show that tough hybrid vesicles can be obtained.

Highlights

Hybrid polymer vesicles are emerging and promising systems that spark an increasing interest from different scientific communities due to their high potentiality in different application fields such as controlled and targeted drug delivery, biomolecular recognition within biosensors for diagnosis, functional membranes for artificial cells, and the development of bioinspired micro/nanoreactors [1,2]
A series of PDMS-b-PEO diblock copolymers of various molar masses and hydrophilic weight fraction was synthesized and their self-assembly was studied in aqueous media
Part of the synthesized copolymers, presenting a hydrophilic fraction around 30%, self-assemble into vesicular structures, whose membrane thickness is modulated via the molar mass of the hydrophobic block according to a scaling law d ~ M0.5, suggesting that PDMS chains are in a coil state in the membrane

Summary

Introduction

Hybrid polymer vesicles are emerging and promising systems that spark an increasing interest from different scientific communities (chemists, physico-chemists, biochemists, biophysicists, and pharmacists) due to their high potentiality in different application fields such as controlled and targeted drug delivery, biomolecular recognition within biosensors for diagnosis, functional membranes for artificial cells, and the development of bioinspired micro/nanoreactors [1,2]. Poly(dimethylsiloxane) [13,14,15,16,17,18,19,20] have been used as hydrophobic block, while studies with poly(isobutene) [21,22,23], poly(caprolactone) [24,25], poly(isoprene) [26], and poly(laurylacrylate) [27]. Poly(ethylene oxide) is by far the most used hydrophilic block, few Polymers 2019, 11, 2013; doi:10.3390/polym11122013 www.mdpi.com/journal/polymers. Polymers 2019, 11, 2013 studies report the use of hydrophilic thermo-responsive blocks such as poly(2-isopropyl-2-oxazoline) [28]. Despite an increasing number of studies, there is still a need of systematic approach to precisely decipher the molecular parameters necessary to associate in an efficient way (i.e., optimized or modulated membrane properties) copolymers and lipids. One of the main ideas is to obtain vesicular structure with lipid in the membrane but presenting high mechanical stability

Methods

Results

Discussion

Conclusion