The surface-dependent biological effect of protein-gold nanoclusters on human immune system mimetic cells

In this paper, the comprehensive toxicity mechanism of four well-defined protein-stabilized gold nanoclusters (Au NCs) is firstly highlighted against promyelocytic leukaemia cells (HL-60). For this purpose, bovine serum albumins (BSA) and human serum albumins (HSA), as well as lysozyme (LYZ) and gamma globulin (gamma G) immunoproteins were applied as reducing and stabilizing agents of the Au nanohybrids. The selected cell line served as an innate human immunity mimetic to detect nonspecific immune responses after the cluster treatments. The surface-dependent comparative study of the synthesized Au-containing systems was determined by several biochemical assays to measure the changes in mitochondrial activity, membrane integrity, and the level of secretion of inflammatory, as well as apoptosis mediators. Besides, the mechanical action and the penetration of the Au NCs were also investigated by confocal microscopy. Based on these experiments, it was proved that the protein-stabilized Au NCs showed a minor toxic effect on HL-60 cells. Although, the clusters did not induce proinflammatory processes but caused noticeable oxidative stress and the apoptosis was also enhanced. In comparison to the surface properties of the Au NCs, it was recognized that the LYZ-stabilized Au NCs had the most negative effect on the HL-60 cells.