Microarray scatter plots. Caco-2 cells were cultured and differentiated for 21 days. The cells were exposed for 72 h at 10 μg/mL of TiO2 STNPs. The scatter plots represent the raw fluorescence intensities of genes signals after hybridization before applying an unpaired t-test statistical analysis and a Benjamini and Hochberg false discovery rate multiple testing correction (n = 4) . A) Negative control: unexposed versus unexposed cells (control 2 versus control1). B) Positive control: H2O2 exposed versus unexposed cells (control). C) Test: T-Lite STNPs exposed versus unexposed cells (control 1). D) Test: T-Lite DL STNPs (UV-degraded) exposed versus unexposed cells (control 2). E) Test: T-Lite DA STNPs (acid degraded) exposed versus unexposed cells (control). Figures C) and D) and E) indicate that STNPs exposed and unexposed cells have similar gene expression. The exact number of altered genes after application of statistical tests is reported in Table 2.