Date of Award
2011
Degree Type
Thesis
Degree Name
Master of Engineering Science
Program
Biomedical Engineering
Supervisor
Dr. Elizabeth R. Gillies
Abstract
Polymer vesicles (polymersomes) are spherical assemblies with aqueous cores, formed
by the self-assembly of amphiphilic polymers in an aqueous environment. They resemble
phospholipid vesicles, but typically exhibit much greater stabilities. The chemical versatility of
the polymer synthesis makes it possible to tune the vesicle characteristics such as vesicle size
and: circulation time in vivo. As such, they are highly promising materials for various
applications including drug delivery. Our research group recently developed a versatile approach
for the conjugation of dendritic groups to the surfaces of polymer vesicles which allows the
surface properties to be readily tuned for specific biological properties or applications. This
thesis will investigate the effects of different dendron functionalities, both neutral and cationic,
on the rate of release of encapsulated small molecules and larger biomacromolecules,
cytotoxicity and the cell uptake properties of polymer vesicles. These properties were explored
in both non-biodegradable vesicles based on polybutadiene-poly(ethylene oxide) (PBD-PEO)
and biodegradable vesicles based on polycaprolactone-poly(ethylene'oxide) (PEOPCL). The
rate of release of an encapsulated small molecule, rhodamine B, was founk to be dependent on
the absence or presence of dendritic functionality. Unlike with small molecules, the release of
encapsulated protein, bovine serum albumin (BSA), depends on the charge of the dendritic
functionalization since both cationic systems exhibited faster, similar release profiles. The
cytotoxicity of the vesicle systems was found to be dependent on their surface charge as toxicity
was observed with both cationic systems at higher concentrations. Finally, the cell uptake was found to be dependent on the functional group displayed on the vesicle surface and guanidine functionalized vesicles had significantly increased cell uptake relative to the other samples.
Recommended Citation
Amos, Ryan C., "Surface Functionalization of Polymer Vesicles with Dendritic Groups: Effects on Physical and Biological Properties" (2011). Digitized Theses. 3516.
https://ir.lib.uwo.ca/digitizedtheses/3516