Fig. 4

The particles increased cell metabolic activity (a) and numbers (b), and concentration of 6MP-AuNPs and 6MP-AuNPs-RDP varied from 0 to 1.0 μg/mL Data are presented as mean ± SEM. The cells with only solvent {0.1 M NaOH (pH 9.0) is adjusted to pH 7.4 by 0.1 M HCl} were used as control. The values were averaged for four independent experiments. ^*p < 0.05, ^**p < 0.01 compared with RDP-treated cells, ^#p < 0.05, and ^##p < 0.01 compared with the 6MP-AuNPs-treated cells