CONICET | Buscador de Institutos y Recursos Humanos

Metal nanoparticles -NP- (10-100 nm) are applied in pharmaceutical products, and the modification with anti-oxidants can improve their properties. The aim of the present work was to investigate differences in the toxicity of metallic gold NP (AuNP) and those modified with cysteine (AuCysNP), on a human cell line.The chemical synthesis of AuNP and AuCysNP was carried out using CTAB (ligand) and sodium borohydride (NaBH4) as a reducing agent: 0.01M AuHCl4; CTAB 0.01M; 10mM NaBH4 and 0.025mM Cysteine. The NPs were characterized by UV/VIS spectroscopy and transmission electronic microscopy (TEM). The HTR-8 / SVneo cell line was incubated for 6 and 24 h at different NPs concentrations (0.01 - 0.5 mM). Cell viability was evaluated by MTT, the production of reactive oxygen species (ROS) by NBT, the levels of nitric oxide by Griess, and the activity of antioxidant defense enzyme, superoxide dismutase (SOD) by riboflavin-NBT method.Exposure for 6 h to AuNP significantly decreased cell viability at 0.2 and 0.5 mM whereas AuCysNP diminished cell viability at 0.5 mM. After 24 h incubation, both NPs significantly modified cell viability at different extent at 0.2 and 0.5 mM, AuNP decreased cell viability a 29 and 68%, while AuCysNP a 19 and 49%, respectively. ROS levels were investigated after 24 h incubation, ROS increased after AuNP (0.1-0.5 mM) incubation, while AuCysNP only increased ROS at 0.5 mM. No changes in nitric oxide levels were observed in the conditions tested. SOD activity was determined after 24 h incubation, an increase in enzyme activity was determined at all the concentrations tested for AuNP and in 0.1; 0.2 and 0.5 mM for AuCysNP, compared to controls.These results suggest that the AuNP modification with the aminoacid cysteine decreases the cell toxicity of AuNP and it may favors an antioxidant response.

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