Figure 3: In vitro expression of the pFDNA-Ag@SiO₂-NPs in 293 T cells detected by the indirect immunofluorescence analysis (×20).

Group A: pFDNA-Ag@SiO₂-NPs; Group B: pFDNA-Ag@SiO₂-NPs treated by DNase I; Group C: Blank Ag@SiO₂ hollow nanoparticles; Group D: 293 T cells as the negative control.