CHARACTERIZATION OF COMPLEXES OF OLIGONUCLEOTIDES WITH POLYAMIDOAMINESTARBURST DENDRIMERS AND EFFECTS ON INTRACELLULAR DELIVERY

This study evaluates polyamidoamine PAMAM ''starburst'' dendrimers (ge neration 3, M-r 6909) as a potential delivery vehicle for oligonucleot ides. Complexes between dendrimer and phosphorothioate oligonucleotide s were observed by agarose gel electrophoresis and were positive, nega tive, or neutral in charge depending on stoichiometry. Complexes were stable in 50% serum to variations in pH (3, 5, and 10) and ionic stren gth (0-500 mM). Ultrafiltration and gel filtration characterization in dicated that the dendrimer:oligonucleotide complexes were primarily <1 00 kD, although some larger complexes were formed at oligonucleotide e xcess. Use of dendrimers resulted in a 50-fold enhancement in cell upt ake of oligonucleotide as determined by flow cytometry, and enhanced c ytosolic and nuclear availability, as shown by confocal microscopy. Th ese data support the further evaluation of dendrimers for oligonucleot ide delivery in cell culture and in vivo.