Faceted polymersomes: a sphere-to-polyhedron shape transformation.

Chin Ken Wong,Robert G Parton,Martina H Stenzel,Pall Thordarson,Matthias Floetenmeyer,Adam D Martin

doi:10.1039/c8sc04206c

Chin Ken Wong, Robert G Parton + Show 4 more

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https://doi.org/10.1039/c8sc04206c

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Abstract

The creation of "soft" deformable hollow polymeric nanoparticles with complex non-spherical shapes via block copolymer self-assembly remains a challenge. In this work, we show that a perylene-bearing block copolymer can self-assemble into polymeric membrane sacs (polymersomes) that not only possess uncommonly faceted polyhedral shapes but are also intrinsically fluorescent. Here, we further reveal for the first time an experimental visualization of the entire polymersome faceting process. We uncover how our polymersomes facet through a sphere-to-polyhedron shape transformation pathway that is driven by perylene aggregation confined within a topologically spherical polymersome shell. Finally, we illustrate the importance in understanding this shape transformation process by demonstrating our ability to controllably isolate different intermediate polymersome morphologies. The findings presented herein should provide opportunities for those who utilize non-spherical polymersomes for drug delivery, nanoreactor or templating applications, and those who are interested in the fundamental aspects of polymersome self-assembly.

Highlights

View Article OnlineUnlike morphological changes that are commonly seen in block copolymer systems (e.g., micelles-to-rods or rods-tolamellae), the shape transformation of spherical polymersomes require an added level of complexity on top of the typical parameters that govern block copolymer self-assembly such as block length and composition, block–block interactions and block–solvent interactions.[40] Generally speaking, in order generate non-spherical polymersomes, one would rst have to select an appropriate combination of block copolymer and solvent system that speci cally targets the spherical polymersome morphology
We show that a perylene-bearing block copolymer can self-assemble into polymeric membrane sacs that possess uncommonly faceted polyhedral shapes but are intrinsically fluorescent
The findings presented should provide opportunities for those who utilize non-spherical polymersomes for drug delivery, nanoreactor or templating applications, and those who are interested in the fundamental aspects of polymersome self-assembly

Summary

View Article Online

Unlike morphological changes that are commonly seen in block copolymer systems (e.g., micelles-to-rods or rods-tolamellae), the shape transformation of spherical polymersomes require an added level of complexity on top of the typical parameters that govern block copolymer self-assembly such as block length and composition, block–block interactions and block–solvent interactions.[40] Generally speaking, in order generate non-spherical polymersomes, one would rst have to select an appropriate combination of block copolymer and solvent system that speci cally targets the spherical polymersome morphology This would have to followed by the introduction of an external factor or force (e.g., osmotic pressure, supramolecular interactions or liquid-crystallinity)[12,19,29] that helps to initiate and direct the shape transformation process. Recently,[19] we reported on the controlled formation of nonspherical (ellipsoidal and tubular) polymersomes (Fig. 1A) via a solvent-controlled supramolecular approach that exploits the use of a carefully designed block copolymer bearing perylene

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