2.7. MTT Cell Viability Assay

Cells were seeded at 4 × 10⁴ cells·mL⁻¹ concentration on a 96-well plate and cultured for 48 h before being treated with NF-GNPs, functionalized GNPs (TfGNPs and AntiEpCamGNPs for SKBR3 and Caco2 cell lines, respectively), or not treated at all in the case of our control cells. Twenty-four hours after GNP treatment, the culture medium was changed and then cells were irradiated at a 3 Gy dose. To determine the impact of treatments on cell viability, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium reduction assay (MTT cell viability assay) was conducted following standard procedures 24 h after irradiation (cat. M2128, Sigma-Aldrich). Viability was calculated in relation to that observed in non-treated cells. Three replicates were carried out for each experimental condition.