Fig. 6

Biological activity of RA released from RAn-CB[6] @AuNRs within leukemia cells. a Schematic representation of the assay. Leukemia cells were treated with AuNR (50 µg/mL) for 4 h, washed with PBS to remove the AuNRs that were not internalised, resuspended in cell culture media, exposed to NIR light for 2 min (780 nm, laser power 2 W/cm²⁾ and cultured for 68 h. At 72 h the cells were analysed by flow cytometry. b Myelocytic differentiation of NB4 cells cultures by varying the amount of RA1 and analysed at 72 h. c RA1 (5 µM) was heated at different temperatures during 5 min before adding to NB4 cells. Cell differentiation at 72 h as assessed by the expression of CD11b⁺ by flow cytometry. d, e Percentages of CD11b⁺ in leukemia cells differentiated for 72 h when cultured with soluble RA1 (1 µM) for the entire duration of the experiment, or incubated for 4 h with RA1-CB[6] @AuNR, washed and immediately irradiated at 0 h (d) or at 24 h (e). Results are expressed as Mean ± SEM (n = 3). Statistical analysis was performed using One-Way Anova followed by Tukey’s post hoc test. * denotes statistical significance (P < 0.05)