Gold nanoparticles and ions – friends or foes? As they are seen by human cells U-937 and HL-60

Abstract

Gold nanoparticles (AuN) are one of the most investigated nanomaterials, finding numerous applications from medicine to industry. AuN were obtained by reduction of gold salts using tannic acid as a reducing agent. To detach the impact of AuN onto cells of two lines human monocytic cells (U-937) and human promyelocytic leukaemia cells (HL-60), the effects of postreaction residues (of effluent from sol cleaning) and gold ions were also examined. It was demonstrated that resistance of cells to the toxic action of AuN is dependent not only on incubation time and dosage, but also on stages of cell differentiation. It was found that after incubation of promonocytes U-937 with 25 ppm AuN, the cell viability decreased by 25% and of macrophages by 50%. Differentiated cells U-937 showed a significantly lower resistance than the not-differentiated cells. For HL-60 cells, regardless of differentiation, cell viability decreased by approximately 20% after treatment with 25 ppm AuN sol. It was noticed that U-937 exhibited higher vulnerability to AuN than HL-60 cells. It was proved that AuN induced over a 15-fold increase in nitric oxide and a decrease of intracellular glutathione levels indicating the inflammatory response of cells. Even though gold ions did not show a significant effect on cell viability, they caused fivefold increase of nitric oxide level. The results show a higher cytotoxicity of AuN than gold ions. An overall picture of the interaction of AuN with human cells of first defence line was obtained. The results indicate that AuN may cause changes in the response of phagocytes in inflammatory conditions.