Synthesis and characterization of a carbon nanotube-dendron series for efficient siRNA delivery

A new series of dendron-functionalized multiwalled carbon nanotube (MWNT) derivatives, characterized by the presence of numerous positively charged tetraalkyl ammonium salts at the periphery of the dendron, has been synthesized. The positive charges on the MWNT surface, coupled with the unique ability of carbon nanotubes (CNTs) to penetrate cell membranes, make the new derivatives potentially ideal vectors for siRNA delivery. Using a fluorescently labeled, noncoding siRNA sequence, we demonstrate that cytoplasmic delivery of the nucleic acid is remarkably increased throughout the different dendron generations. The work reported here highlights the fact that dendron-functionalized CNTs can be rationally designed as efficient carriers of siRNA that can eventually lead to gene silencing. or macromolecules other than DNA and develop the rationale behind using Ads for such applications. Due to the modular nature of the Ad capsid, multiple therapeutic or diagnostic modalities, such as the addition of magnetic resonance imaging  contrast agents, radiation sensitizers and antigenic peptides for vaccines, can be incorporated by modifying different sites on the viral capsid. These types of particles have a tremendous potential to increase the sensitivity and specificity of therapies.