2.9. Cell Culture

The cytotoxicity and transfection potential of prepared polyplexes were evaluated in U2OS (human bone osteosarcoma epithelial) and SCC-9 (human oral squamous cell carcinoma) cells. The cells were incubated at 37 °C in a 5% CO₂ atmosphere in appropriate cell culture medium (DMEM:F12 for SCC-9 and McCoy’s 5A medium, respectively) supplemented with 10% (v/v) heat-inactivated FBS, penicillin (U mL⁻¹) and streptomycin (100 μg mL^–1). Hydrocortisone (400 ng/mL) was added to DMEM:F12. Cells were grown in monolayers and detached by treatment with a 0.25% trypsin solution (Sigma, St. Louis, MO, USA).