the present invention relates to delivery of biologically active molecules to cells . specifically , the invention relates to polycationic compositions , polymers and methods for delivering nucleic acids , polynucleotides , and oligonucleotides such rna , dna and analogs thereof , including short interfering rna , ribozymes , and antisense , or peptides , polypeptides , proteins , antibodies , hormones and small molecules , to cells by facilitating transport across cellular membranes epithelial tissues and endothelial tissues . the compositions and methods of the invention are useful in therapeutic , research , and diagnostic applications that rely upon the efficient transfer of biologically active molecules into cells , tissues , and organs .