Fig. 2. Effects of the SeNPs, Se@β-CD-FA and Se@β-CD-FA@PTX on the growth of MCF-7 cells by MTT assay. (A) Antiviral activity of Se@β-CD-FA@PTX. The concentration of the SeNPs, Se@β-CD-FA and Se@β-CD-FA@PTX was 50 μg ml⁻¹, PTX was 8 μg ml⁻¹, and the Se@β-CD-FA@PTX conjugates were at a PTX dose of 8 μg ml⁻¹. (B) Morphological changes in the MCF-7 cells observed by phase-contrast microscopy. The asterisks over the bars indicate the statistical difference at the *p < 0.05 or **p < 0.01 level.