Comparative Analysis of Polyethyleneimine Efficiency for Improvement of Plasmid DNA Bioavailability

We studied the influence of the type and structure of polyethyleneimine on bioavailability and expression of plasmid DNA carrying IGF-1 gene. Polymers with different molecular weights (2.5, 10, 25, and 60 kDa) of linear and branching structure were studied. It was found that the time of polyplex circulation in the blood did not exceed 24 h and the maximum concentration of plasmid DNA was attained with complexes with a molecular weight of 60 kDa. Analysis of liver samples showed that administration of 60-kDa branched polyethyleneimine complex provides DNA protection from degradation for 4 h; in 24 h from the start of the experiment, its concentration was significantly higher than the concentration of other studied polyethyleneimines. The expression of plasmid IGF-1 DNA for this complex attained maximum in 4 h and was equal to 15.50 (7.98; 21.98) arb. units/ml. These results allow us to recommend using polyethyleneimines with branched structure and a molecular weight of 60 kDa for improving plasmid DNA protection and bioavailability.