Measurement of cell viability

To determine IC50 concentrations of CT20p, cells at 60% confluency were treated with a dose range of CT20p-HBPE-NPs for 48 hours. Cell viability was determined using CellTiter-Glo Luminescent Cell Viability Assay (Promega). IC50 determination was performed with Graphpad Prism software. To determine populations of live, apoptotic, and necrotic cells, cells were treated with CT20p-HBPE-NPs (75 μg nanoparticles/mL). After defined time points, cell death discrimination was performed with the Sytox AADvanced and F2N12S Violet Ratiometric Apoptosis kit (Invitrogen). Data was acquired by flow cytometry on a FACS Canto (BD Biosciences), and analyzed with FCSExpress software (DeNovo).