This invention relates compositions and methods for increasing the uptake of polynucleotides into cells. Specifically, the invention relates to vectors, targeting ligands, and polycationic agents. The polycationic agents are capable of (1) increasing the frequency of uptake of polynucleotides into a cell, (2) condensing polynucleotides; and (3) inhibiting serum and/or nuclease degradation of polynucleotides.