Fig. 5

Uptake and transfection of naked and shielded particles. A Time-dependent uptake of PBMD(pDNA) particles with and without shielding polymer (N/P 10, L/C 0.6, 1 µg mL⁻¹ YOYO-1 labeled pDNA) in HEK293T and K-562 cells. The relative mean fluorescence intensity (rMFI) of viable single cells was calculated relative to the control (particle w/o YOYO-1) (n = 3 ± SD). Statistical significant differences between naked and shielded PBMD(pDNA) particles at the respective timepoint are indicated as follows: *p < 0.05, **p < 0.01, and ***p < 0.001. B Transfection efficiency (percentage of viable fluorescent EGFP-expressing cells) in HEK293T cells was measured after incubation with the particles (N/P 10, L/C 0.6, 0.5–4 µg mL⁻¹ pDNA) for 24 h or 1 and 4 h followed by subsequent incubation with fresh media for 24 h. C K-562 cells were transfected with the particles (N/P 10, L/C 0.6, 0.5–6 µg mL⁻¹ pDNA) for 48 h. B, C Cytotoxicity was evaluated according to the SSC/FSC pattern (mean of n ≥ 3 ± SD). The dashed line indicates 70% cell viability. Asterisks indicate significant differences between naked and shielded PBMD(pDNA) particles at the respective timepoint and concentration: *p < 0.05, **p < 0.01, and ***p < 0.001. Significant differences in comparison to the respective control (Viromer® RED (Viro) at 1 µg mL⁻¹ pDNA and LPEI at 4 µg mL⁻¹ pDNA) are indicated as follows: #p < 0.05, ##p < 0.01, and ###p < 0.001