Date of Award

Spring 5-1-2021

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

School

Polymer Science and Engineering

Committee Chair

Dr. Yoan C. Simon

Committee Chair School

Polymer Science and Engineering

Committee Member 2

Dr. Xiaodan Gu

Committee Member 2 School

Polymer Science and Engineering

Committee Member 3

Dr. Charles L. McCormick

Committee Member 3 School

Polymer Science and Engineering

Committee Member 4

Dr. Sarah E. Morgan

Committee Member 4 School

Polymer Science and Engineering

Committee Member 5

Dr. Derek L. Patton

Committee Member 5 School

Polymer Science and Engineering

Abstract

Polymersomes, also known as polymer vesicles, have gained a lot of interest over the past two decades. These hollow spherical systems are made via the self-assembly of amphiphilic block copolymers and have found use in a range of areas from drug delivery, to cellular models, to nanoreactors. Their hollow nature allows them to carry hydrophilic cargo in their inner compartment and hydrophobic cargo in their membrane. Over the last decade, increasing efforts have focused on controlling the morphology of polymersomes. Research has shown that polymersome morphology plays an important role for instance in drug delivery, where tubular or rod-like vesicles have been shown to have better pharmacokinetics than the traditional spherical morphologies. The following work explores the development of polymersomes with non-spherical morphologies using polymer vesicles with glassy hydrophobic membranes.

After a comprehensive introduction topic in Chapter I, Chapter II focuses on the synthesis of an amphiphilic ABA triblock copolymer and how the block copolymer composition and hydrophilic volume fractions impact the formation of vesicles. We then investigated the polymer membrane response to light-triggered photocrosslinking and osmotic pressure changes using different stimuli. We showed the transformation of these polymersomes into tubular polymersomes via a combination of crosslinking and slow osmotic pressure changes via dialysis. We also demonstrated that these polymersomes could be transformed into a range of different non-spherical morphologies by inducing rapid osmotic pressure changes using a fusogen.

In the third chapter, we explored the differences in bending rigidity between polymersome membranes from amphiphilic diblock and triblock copolymers. We demonstrated that polymersome membranes from the latter have higher rigidity and a lower threshold for hydrophobic block molecular weight and volume fraction to maintain non-spherical polymersome morphologies. Chapter IV describes our attempts to fabricate non-spherical polymersomes with asymmetric membranes to facilitate the formation of morphologies suited for multi-compartmentalized, cell and organelle mimics. Finally, Chapter V offers a concise summary of our work and explores future directions that will be explored using the reported work as a foundation.

ORCID ID

0000-0002-7920-5804

Available for download on Saturday, March 25, 2023

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