Characterization of Complexes of Oligonucleotides with Polyamidoamine Starburst Dendrimers and Effects on Intracellular Delivery

Abstract

This study evaluates polyamidoamine PAMAM "starburst" dendrimers (generation 3, Mr 6909) as a potential delivery vehicle for oligonucleotides. Complexes between dendrimer and phosphorothioate oligonucleotides were observed by agarose gel electrophoresis and were positive, negative, or neutral in charge depending on stoichiometry. Complexes were stable in 50% serum to variations in pH (3, 5, and 10) and ionic strength (0-500 mM). Ultrafiltration and gel filtration characterization indicated that the dendrimer:oligonucleotide complexes were primarily < 100 kD, although some larger complexes were formed at oligonucleotide excess. Use of dendrimers resulted in a 50-fold enhancement in cell uptake of oligonucleotide as determined by flow cytometry, and enhanced cytosolic and nuclear availability, as shown by confocal microscopy. These data support the further evaluation of dendrimers for oligonucleotide delivery in cell culture and in vivo.

A Surface‐Modified Dendrimer Set for Potential Application as Drug Delivery Vehicles: Synthesis, In Vitro Toxicity, and Intracellular Localization

“…Dendrimers were not only found inside the nucleus but also at other sites in the cell, presumably at the plasma membrane and in endomembrane compartments. [32,58] As shown in Figure 9 and Figure 10, none of the dendrimers investigated in this study displays a localization inside of the nucleus. Instead, they are rather always found directly next to the nucleus.…”

Nanoparticle Targeting of Anticancer Drug Improves Therapeutic Response in Animal Model of Human Epithelial Cancer

“…Polyamidoamine dendrimers are well-characterized, highly branched synthetic macromolecules that are biocompatible and nonimmunogenic, providing a unique platform for delivery of a variety of therapeutic agents, imaging agents, and oligonucleotides (13)(14)(15)(16)(17)(18)(19). We have reported previously the synthesis of folic acid-conjugated, surface-modified PAMAM dendrimers and have shown in vitro the highly selective binding and internalization of these polymers in tumor cells that overexpress folate receptor (20).…”

Tat-Conjugated PAMAM Dendrimers as Delivery Agents for Antisense and siRNA Oligonucleotides

“…Dendritic polymers such as PAMAM dendrimers have been extensively used as carriers for plasmid DNA (9,10) and for antisense oligonucleotides (11,12). Cationic dendrimers may have some advantages over other types of positively charged carriers such as cationic lipids in that the dendrimerYoligonucleotide complexes are of macromolecular size (13) and dendrimers are known to have extended lifetimes in vivo (14), whereas cationic lipid complexes are large particles that are usually rapidly cleared from the circulation by splenic and hepatic phagocytes (15).…”