Gold nanoparticles effects on neurite outgrowth were assessed by measurement of neurite outgrowth in differentiating mouse neuroblastoma cell line NB2a exposed to 5 nm, 10 nm and 15 nm conventional gold colloids and monolayer protected clusters. Neurite outgrowth enhancement was the predominant effect of most particles types. The thesis also investigated the uptake and intracellular fate of gold nanoparticle in the NB2a cell line in a serum free environment, employing a 2-D profile-based counting method. It was found that the monolayer clusters were taken up in significantly less amounts than their conventional counterparts following 24 hour exposure. No evidence for cellular accumulation was found after seven days as particle clearance was shown to be greater than 90 %. In addition, the thesis describes the development of functionalised monolayer protected gold clusters for application in bilirubin extraction. Bilirubin neurotoxicity was determined by measuring neurite outgrowth in NB2a cells and the application of the gold nanoparticle system in ameliorating this effect was attempted. No significant changes were observed. The presence of virus-like particles in the neuroblastoma cell line was investigated in the line of a potential confounding factor to the observed toxicity results. The thesis therefore also describes the morphology and genomic features of a virus-like particle. The morphological appearance describes intracisternal A-particles (IAP) but the nucleotide sequence revealed evidence of the B-tropism of mouse leukaemia viruses suggesting a rare form of an infectious IAP. The finding of an infectious IAP in mouse NB2a cell has implication for the continued use of this cell line.