Figure 6.

Metabolic activity of (A) AGS and (B) MKN74 cell lines after direct contact with NP (direct contact, ISO 10993-5; 12). Cell metabolic activity was assessed by the resazurin assay after 24 h incubation with NP (NorChit-NP and AMP-NP), no treated cells (TCPE; negative control), or 1 mM 30% V H₂O₂ (positive control). Metabolic activity is expressed as the percentage of the cell metabolic activity of treated cells in relation to cells in culture medium only. *NorChit-NP is significantly different from cells in culture medium only; *** positive control is significantly different from all other samples (one-way ANOVA, followed by Tukey’s multiple comparison test, p < 0.05). (C) AGS and (D) MKN74 morphology were analyzed by cytochemistry: cells were stained with DAPI (nucleus)—blue and phalloidin (F-actin in cytoskeleton)—green. Fluorescence images were taken by IFM after contact with NP. Cells cultured in the presence of H₂O₂ died and therefore detached from the bottom of the plate, the reason why no cells were seen after staining. Magnifications = 200× and 400×; scale bar = 100 μm for background image and 50 μm for inserts.