4.7. Cell Viability Assay

Transfected cells were fixed with 4% formaldehyde in phosphate-buffered saline (PBS) for 5 min at RT. After washing three times with PBS, the fixed cells were incubated with RNase A (100 ug/mL) for 20 min and incubated with PI (250 ng/mL) for 15 min at 37 °C in a CO₂ incubator. After washing three times with PBS, stained cells were counted using an LSM-700 confocal microscope (Carl Zeiss).