Biological properties of MAG-ARA/DOX NPs. (a) In vitro toxicity and efficacy of MAG-ARA/DOX NPs (MAG-ARA/DOX) in comparison to soluble DOX (DOX) and nonfunctionalized MAG-ARA NPs in three different concentrations. Experiments were performed in MDA-MB-231 cells and viability was assessed with MTT colorimetric assay. Viability is calculated as percentage of absorbance of untreated cells. (b) Bargraph indicating tumor volumes of MDA-MB-231 xenografts treated with MAG-ARA/DOX, soluble DOX (DOX) and vehicle (control), at the time therapy commences (Day 0) and 7 or 14 days later. MAG-ARA/DOX NPs used in these experiments were also coated with FA-PEG2000. *Designates P value < 0.05 and ***designates P value < 0.001.