Percentage of EGFP gene silencing at day 5 of transfection by CS/siRNA complexes formulated with a CS-Asp of different MWs (20, 45, 200, and 460 kDa) and b CS MW 20 kDa of different salt (CS-HCl, CS-Asp, CS-Glu, and CS-Ac) at various weight ratio of 4 (), 8 (), 16 (□) and 32 (■) in HeLa cells stably expressing EGFP. Each value represents the mean ± SD of three wells. Differences values * were statistically significant (P < 0.05)