Cell cycle analysis by flow cytometry

Flow cytometric analysis was performed to study the effect of various formulations of drug/QD complexes in the presence and absence of siBcl-2 (50 nM) on the cell cycle of A549 cancer cells. Free drugs at the same concentrations as the encapsulated drugs were used as controls to illustrate the effect of the delivery systems (Carbo: 500 nM; Tax: 0.03 nM; Dox: 32 nM). After treatment with drug/QD complexes for 24 hours, cells were washed with PBS, resuspended at 50 µg/mL in PBS solution containing 0.1 mg/mL RNase A and 0.05% Triton X-100, and incubated at 37°C for 30 minutes. Afterward, the samples were analyzed on a FACSCalibur Cell Analyzer (BD Biosciences, San Jose, CA, USA). Data analysis was conducted by ModFit LT 3.2 software.