Fig. 4

Illustration of AGuIX^® NP uptake measured by FCM as a function of time in the 3 OncoCilAir™ subpopulations. a Summary of AGuIX^® uptake with the percentage of AGuIX^®+ cells and their corresponding MFI values presented after 24 and 72 h of NP exposure (n = 6/conditions, from 3 distinct batches of cell culture with and without mucus). The relative uptake ratios were calculated from Eq. 3. Statistical analysis was performed using the Mann–Whitney test (*p ≤ 0.05 compared to GFP-negative cells). The results b–i were obtained from samples of the 2nd series of cell cultures, presenting a fast tumor growth and an intense AGuIX^® uptake at T24h. FACS plots of AGuIX^® uptake (% of AGuIX⁺-cells and geometric mean MFI) according to the 3 gates (b, f) that discriminate GFP-negative (red channel; c, g), GFP⁺ (green channel; d, h) and GFP⁺⁺ (blue channel; e, i) tumor cells at 24 h (b–e) and 72 h (f–i)