Fig. 4

AuNPs induced pro-inflammatory response of THP-1 cells. Secretion of CCL2 (a, e), TNF-α (b, f), IL-6 (c, g) and IL-1ß (d, h) from PMA-stimulated cells, in response to Au_SC, Au_CHIT-L, and Au_CHIT-H; 1 ng/ml LPS was used for co-stimulation; with 1 and 100 ng/ml LPS for controls; results are expressed as cytokine release in pg/ml, and each data point represents the mean ± SEM of three independent biological replicates; statistical significance (determined by ANOVA with Tukey posthoc) is shown by *p < 0.05, compared to relevant controls (1 ng/ml LPS); or by Spearman’s rank correlation coefficient to assess the NP dose dependent relationship with cytokine release, where Ζ = p < 0.05