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Title: Designer peptide markers towards multifunctional nanoprobes for cellular targeting at the nanoscale
Author: Rakowska, P. D.
ISNI:       0000 0004 5358 9111
Awarding Body: University College London (University of London)
Current Institution: University College London (University of London)
Date of Award: 2014
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The project investigated the development of peptide-based nanotools for applications in cell biology. Differential intracellular and membrane targeting was probed using rationally designed cell penetrating and antimicrobial peptides. The interaction of the peptides with bacterial and mammalian membranes was imaged using a combination of atomic force microscopy (AFM) and highresolution secondary ion mass spectrometry (NanoSIMS). This approach provided unique information on the topography of peptide-treated membranes, obtained from AFM images, suggesting membrane changes as a result of peptide structuring and pore formation. The data was complemented by chemical imaging performed on the same samples with NanoSIMS, which revealed the precise localisation of peptide molecules in the membranes. In parallel, multidimensional protocol for tag-free quantification of cellular uptake of cell penetrating peptides, based on chromatographic separations and followed by isotope dilution mass spectrometry was developed. The amount of the designed peptide, internalised by human dermal fibroblasts was evaluated and compared to the uptake of a broadly studied and well characterised naturally occurring peptide. The results were compared to the peptide uptake quantified using confocal fluorescence microscopy. The studied synthetic peptides were also investigated as model systems to functionalise metallic nanoparticles (NPs). Characterisation and functionalisation of the NPs were carried out. To prevent a non-specific physisorption of molecules, the surface of NPs was passivated by coating with lipid bilayer or polyethylene glycol. Finally, using cross-linking chemistry, the designed peptides were conjugated to the coated particles and their interaction with mammalian and microbial cells was investigated by transmission electron microscopy. The results of this work indicate that rationally designed peptides carry the potential for being employed in the development of nanoscale, multifunctional probes for differential and specific intracellular and extracellular targeting.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available