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The study of vesicle phoresis in a concentration gradient

Almadhi, Safa Ali; (2022) The study of vesicle phoresis in a concentration gradient. Doctoral thesis (Ph.D), UCL (University College London). Green open access

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The targeted delivery of drugs to specific diseased sites within the body is one of the major issues in the development of drug delivery today. This is particularly relevant in addressing central nervous system (CNS) disorders and diseases, diseases localised in the brain and spinal cord, where the delivery of the therapeutics is limited by the brain barriers. Consequently, the design of drug delivery systems able to independently navigate within the body to specifically deliver the cargo into the brain is desirable. Inspired by nature, scientists have created artificial self-propelling micro and nanoparticles, known as micro- or nano- swimmers. This thesis focuses on the self-assembly and migration of vesicular nanoparticles within a glucose gradient as potential nanoswimmers. Two types of nanoparticles are explored: a) bi-component PMPC-PDPA:PEO-PBO polymersomes and b) α-hemolysine-porated liposomes. First, a methodology to self-assemble the PMPC-PDPA:PEO-PBO polymersomes is optimised to attain a monodisperse, vesicular sample. This was followed by the incorporation of glucose oxidase enzyme into both the polymersomes and liposomes with an average of 6 and 16 enzymes per nanoparticle respectively. The diffusioosmotic drift and the background convection of the fluid within the glucose gradient in presence of the nanoparticles was then investigated. It is found that velocities of the fluid significantly vary by the mere introduction of a nanoparticle into the gradient. Velocity profiles of each nanoparticle in the glucose gradient were developed isolating the diffusioosmotic drifts. Finally, the diffusiophoretic and chemotactic components of the nanoparticles were quantified and isolated. It was found that the polymersomes experience higher mean-square displacement with directed self-propulsion velocities towards the region of higher glucose concentration. The liposomes experience a strong diffusioosmotic drift away from the glucose gradient, nevertheless, a slight reduction in these velocities was observed suggesting self-propulsion of the active liposomes towards the glucose incapable of overcoming the diffusioosmotic drift.

Type: Thesis (Doctoral)
Qualification: Ph.D
Title: The study of vesicle phoresis in a concentration gradient
Open access status: An open access version is available from UCL Discovery
Language: English
Additional information: Copyright © The Author 2022. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request.
UCL classification: UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Chemistry
UCL > Provost and Vice Provost Offices > UCL BEAMS
URI: https://discovery.ucl.ac.uk/id/eprint/10152891
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