Figure 3.

Cell viability assessed by trypan blue exclusion. Nanoparticles MNP-PEI and MNP-PEI-PEG at 1.56 (white bar), 3.125 (light grey bar), 6.25 (grey bar), 12.5 (dark grey bar) and 25 μg mL^-1 (black bar) were incubated with SH-SY5Y and RAW 264.7 cells over a period of 168 h. A1 MNP-PEI nanoparticles incubated with SH-SY5Y cells, A2 MNP-PEI nanoparticles incubated with RAW 264.7 cells, B1 MNP-PEI-PEG incubated with SH-SY5Y cells and B2 MNP-PEI-PEG incubated with RAW 264.7 cells. Experiments were performed three times, and data were expressed as mean ± standard errors. Asterisk denotes significant decrease in viability compared with control cells; square denotes significant increase in cell viability compared to MNP-PEI samples at a similar concentration and incubation time (p < 0.05).