Cell viability of polymer (A) only PCDP and (B) only PEI 25 kDa and various polyplexes (C) in A549, Huh-7, and Mia PaCa-2 cells. The numbers in the bottom refer to the mean concentration of polymer ranging from 1 to 20 µg/mL (A and B) and weight ratios of PCDP/pDNA polyplexes based on pDNA (gWiz-Luc, 500 ng) (C). Poly(CBA-DAH), PEI 25 kDa, and Lipofectamine® were formed the polyplexes with pDNA at weight ratio 1:40, 1:1, and 1:2, respectively. Results are represented as mean ± SD. (n=3). ***P <0.001 versus PEI 25 kDa.