Transfection of stearic acid (SA)-modified p [HPMA- co -K
] polyplexes in HeLa cells. HeLa cells were treated with polyplexes (containing 1 μg plasmid DNA) at charge ratios (N/P) of 3, 5, and 10 for 4 h in serum-free conditions, washed, and replenished with complete media. At 48 h post-transfection, cell lysates were assessed for (A) luciferase reporter gene expression and (B) protein content as an indicator for cytotoxicity. Data are presented as the mean ± S.D., n = 3.