Nanoparticles for targeting cancer tissue: detection and imaging

Watson, Luke Simon (2023). Nanoparticles for targeting cancer tissue: detection and imaging. University of Birmingham. Ph.D.

Preview

Watson2023PhD.pdf
Text - Accepted Version
Available under License All rights reserved.
Download (9MB) | Preview

Abstract

Gold nanoparticles have been widely used for a plethora of applications including bio-imaging agents through reflectance based microscopy, conjugation of luminescent metal complexes and specific targeting through the conjugation of proteins, antibodies and small molecules. Luminescent metal coated gold nanoparticles offers many advantages including dual emission through the triplet metal-to-ligand charge transfer (3MLCT) and by reflectance of the gold, reduced toxicity and issues concerning cellular uptake. Three ruthenium(II) complexes were evaluated for their photophysical properties in aerated water, in the presence of a fluorosurfactant and decorated on 13 nm gold nanoparticles. The selection of the ruthenium(II) decorated gold nanoparticle system expressing the greatest photophysical properties was explored for its ability as a live cell imaging probe. It was found that the phenanthroline ruthenium(II) complex displayed longer luminescence lifetimes and higher quantum yields in agreement with previous studies. Live cell imaging in A549 cells were performed revealing localisation in the cytoplasm and perinuclear compartments. Additionally, a novel osmium(II) complex based on its previously made bipyridine counterpart for the attachment onto gold nanoparticles was synthesised for live cell imaging. Upon binding to the gold nanoparticles, luminescence of the osmium(II) complex was detected yielding, to our knowledge, the first example of a luminescent osmium(II) decorated gold nanoparticle. Upon confirmation of the phenanthroline ruthenium nanoprobes ability to image live cells, 13 nm gold nanoparticles were conjugated directly to the CD20 monoclonal antibody, Rituximab, for specific targeting of B cell malignant cells. Three cell lines (Jurkat – T-lymphocyte, Raji – B-cell Burkitt lymphoma, and Karpas 422 – B-cell Non-Hodgkin lymphoma) were evaluated with the Rituximab and ruthenium(II) functionalised gold nanoparticles to determine preference towards the overexpressed B-cell receptor of interest, CD20. Flow cytometry analysis confirmed preference towards B-cell lines overexpressing CD20 with Rituximab gold nanoparticles however the difference in intensity could not be statistically analysed based on one biological repeat. Confocal microscopy imaging of these particles on tonsil tissue revealed stronger intensities in fluorescence with the particles containing Rituximab than those without. Further proof of specific targeting of the ruthenium(II) and Rituximab nanoprobe was ascertained from mass spectrometry imaging yielding a higher ion intensity map in both the central and outer-part of the tissue sections. These results demonstrate the application of this nanosystem as a dual imaging nanoprobe for bio-imaging and mass spectrometry imaging.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):