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Title: Interactions of nanoparticles with cells for nanomedical applications
Author: Stevenson, Amadeus
ISNI:       0000 0004 5356 7764
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 2014
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Nanotechnology is a rapidly growing field focused on the manipulation and control of materials with dimensions under 100 nm. The novel electronic, optical and mechanical properties observed at the nanoscale have resulted in a number of applications in catalysis, light emitting devices, solar power, self-cleaning surfaces and medicine. Medical applications of nanotechnology (“nanomedicine”) are particularly promising for rapid clinical diagnosis and targeted treatments. Understanding the interactions of nanoparticles with living matter is of fundamental importance for all application areas: manufacture, use and disposal of the growing number of nanoproducts will result in increased environmental exposure in addition to direct exposure through nanomedical applications. However, there is a lack of standard methodologies for assessing these interactions. In this work the stability of silver-based nanoparticles was established by UV- Visible (UV-Vis) spectroscopy, atomic force microscopy (AFM) and transmission electron microscopy (TEM). The presence of a higher valence metal or polymer on the nanoparticle surface was demonstrated to improve stability. A standard methodology was developed to study nanoparticle-cell interactions: an “atlas” of the effects of known drugs on a cell is created, and compared with the effects of a nanoparticle. Escherichia coli was selected as a model organism and the effects of a range of antibiotics were characterised through a combination of microbiological assays and AFM. Susceptibility, population cell growth and individual heights, widths, lengths and volumes of bacteria were obtained on a 2% agarose substrate in air. The methodology was applied and adjusted for silver nanoparticles due to the interactions of silver with the bacterial growth medium. 10 and 30 nm silver nanoparticles and ions were found to kill E. coli through an internal mechanism of action, with a size-specific effect on the height of bacteria. Finally, a novel AFM characterisation method is described to examine the mechanical properties of live bacterial and human cells in liquid.
Supervisor: Trigueros, Sonia Sponsor: Engineering and Physical Sciences Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Biophysics ; nanotoxicology ; methodology ; nanotechnology ; toxicology ; nanomedicine ; silver ; E. coli ; bacteria ; red blood cells ; atomic force microsocopy ; Escherichia coli ; nanoparticles ; nanomaterials