Size (graph A) and zeta potential (graph B) of polyplexes CS0, CS3, CS5, 15:1-CS3, 15:1-CS5, all with 100 µg of NLS (the graphs are representative for S and T co-complexation formulations) and covalently bond NLS formulations (CSedac3 and CSedac5).Polydispersity was below 0.4. Statistical differences of each condition compared to polyplexes without NLS peptides (CS0) were calculated using Dunnett’s multiple comparisons test; N=3, error bars = SD; **P<0.01; *P<0.05.