Figure 6. TUNEL assay performed 24 h after the PEI-DNA nanoparticles treatment showed that tested nanoparticles do not cause HCF death. No significant differences in TUNEL+ cells (Red) were seen in the untreated A: and nanoparticle-untreated B: HCF at 24 h. Nuclei are stained blue with DAPI. Scale bar denotes 100 μm.