Synthesis and Functional Evaluation of DNA-Assembled Polyamidoamine Dendrimer Clusters for Cancer Cell-Specific Targeting

Abstract

We sought to produce dendrimers conjugated to different biofunctional moieties (fluorescein [FITC] and folic acid [FA]), and then link them together using complementary DNA oligonucleotides to produce clustered molecules that target cancer cells that overexpress the high-affinity folate receptor. Amine-terminated, generation 5 polyamidoamine (G5 PAMAM) dendrimers are first partially acetylated and then conjugated with FITC or FA, followed by the covalent attachment of complementary, 5'-phosphate-modified 34-base-long oligonucleotides. Hybridization of these oligonucleotide conjugates led to the self-assembly of the FITC- and FA-conjugated dendrimers. In vitro studies of the DNA-linked dendrimer clusters indicated specific binding to KB cells expressing the folate receptor. Confocal microscopy also showed the internalization of the dendrimer cluster. These results demonstrate the ability to design and produce supramolecular arrays of dendrimers using oligonucleotide bridges. This will also allow for further development of DNA-linked dendrimer clusters as imaging agents and therapeutics.

Molecular Dynamics Studies of the Size, Shape, and Internal Structure of 0% and 90% Acetylated Fifth-Generation Polyamidoamine Dendrimers in Water and Methanol

“…Sci. 35, 2913-2924 and in water by Choi et al (Nano Letters,4,[391][392][393][394][395][396][397]. Calculation of the moments of inertia and the relative shape anisotropy show that both 0% and 90%-acetylated G5 are modestly ellipsoidal.…”

Polymeric micelle-based bioassay with femtomolar sensitivity

“…This creates a highly sensitive bioassay due to the signal amplification process, in which one binding event translates into the fluorescence signal of hundred thousands of dye molecules released from a single polymeric micelle to the solution. While linking an antibody molecule with many dye molecules has been an effective way to increase an assay's sensitivity, it has typically been achieved by attaching the antibody to dendrimers or particles [8,9,10], on which the dye molecules were attached on the surface. In our case, the dye molecules are encapsulated inside the micelles.…”

Hydrophobization and bioconjugation for enhanced siRNA delivery and targeting

“…These surface amino groups provide useful moieties for the functional modification of dendrimers since they allow covalent coupling reactions under mild conditions and in a controlled fashion (Mahato et al 1999). Although pAMAM dendrimers have been largely applied for delivery of plasmids and ODNs (Santhakumaran 2004;Hollins 2004;Choi 2005), this strategy remains to be explored for siRNA delivery. Generally, it is expected that the advantages observed for ODNs may be adapted for siRNA.…”