Guanidiniocarbonyl pyrrole (GCP) conjugated PAMAM-G2, a highly efficient vector for gene delivery: the importance of DNA condensation.

A novel hybrid compound 1 efficiently shuttles genetic material into HeLa cells at concentrations as low as 0.6 mu M, whereas the parent compound PAMAM-G2 is ineffective even at 200 mu M. The high efficiency of 1 stems from its capabiliy to form highly condensed ligand-DNA polyplexes. Its binding affinity is actually lower than for the parent dendrimer. Compound 1 is even 200 times more effective and less cytotoxic than PEI, the current gold standard in gene transfection with cationic polymers.