Gold Nanoparticles as Adjuncts in Electrophoretic Analysis of Biopolymers

This thesis discusses two projects which investigate the analysis and application of biomolecules. Chapter 1 provides the background and context of this work. Chapter 2 discusses the synthesis and characterisation of three types of gold nanoparticles, sodium citrate, cetyltrimethyl ammonium bromide (CTAB) and 4-dimethylamino pyridine (DMAP) protected gold nanoparticles, as well as two types of polyacrylamide gel, TBE and tris-HCl. Successful characterisation of these gold nanoparticles was carried out by dynamic light scattering, ultra-violet visible spectroscopy and transmission emission microscopy. The characterisation of polyacrylamide gels was achieved by investigation by rheology, optical coherence tomography and scanning electron microscopy. Rheological analysis demonstrated that the addition of gold nanoparticles to polyacrylamide reduces the elasticity of the gel but stabilises the linear viscoelastic range, while not changing the core properties of the material. These materials were then used to separate sulfur containing biomolecules by polyacrylamide gel electrophoresis.

Chapter 3 discusses the efficacy of the three types of gold nanoparticles to separate sulfur containing biomolecules when added to polyacrylamide gel electrophoresis. Citrate and CTAB gold nanoparticles where unsuccessful when used to analyse phosphorothioated DNA, however, DMAP gold nanoparticles showed promising results. DMAP gold nanoparticles were further tested with the proteins lysozyme, bovine serum albumin (BSA), glutathione-S-transferase (GST) and RNAse A (RNAse). The retention of BSA and GST was successful however there was continued problems with visualising lysozyme and RNAse. This led to the development of ATP polyacrylamide gel electrophoresis.

Chapter 4 discusses the theoretical application of the development of catalytic DNA aptamers using in vitro selection. We synthesised a DNA aptamer library, two primers and two biotinylated strands of DNA, to be used in the selection process. However due to poor purity and yields, the project remains in its infancy. We discuss the methods by which we would conduct this research and our justifications for these processes.