Engineering of a specific binding site for protein labelling with luminescent lanthanide coated nanoparticles: a study of protein labelling and nanoparticle-peptide interactions

The work presented in this thesis investigates the use of new luminescent lanthanide complexes, both free and bound to the surface of gold nanoparticles, for protein labelling. Lanthanide complexes were shown to maintain their luminescence properties when conjugated to proteins and one complex also demonstrated participation in Förster resonance energy transfer when conjugated to a protein in an appropriate system. Furthermore, it was found that bovine serum albumin can act as a vehicle to transport luminescent lanthanide complexes into two human cell lines. Lanthanide complexes were then used to coat 13 nm gold nanoparticles for protein labelling within cells. The aim was to find a peptide sequence to preferentially bind to gold nanoparticles which could be expressed as part of a protein of interest, acting as a binding site within the cell. The interaction of peptides with gold nanoparticles was examined using several methods and, of the sequences tested, CCPGCC was found to have the highest affinity for the nanoparticles. This peptide was expressed in HeLa cells as part of green fluorescent protein. Co-localisation of the nanoparticles with the protein in cells could not be established through fluorescence microscopy, however, cell lysis revealed green fluorescence protein associated with nanoparticle aggregate