Figure 3.

Dox efficacy. Metabolic activity of MDA-MB-231 breast cancer cells after treatment with free Dox, NP50@Dox, and NP70@Dox at final drug concentrations of 8, 2, 0.5, 0.125, and 0.03 μM for 24, 48, and 72 h of culture. Cells treated with the same volume of vehicle (ultrapure water) or 300 μg/mL of empty NPs were used as no treated (NT) and control (CTR), respectively. No differences between these two conditions were measured, and, as such, the results were normalized against the CTR. Dotted line is utilized to signify the NT condition, facilitating a straightforward comparison with the various treated conditions. Letters denote significant differences between conditions at the same concentration: d = p < 0.0001, c = p < 0.001, b = p < 0.0, and a = p < 0.05.