Ammonium and guanidinium dendron-carbon nanotubes by amidation and click chemistry and their use for siRNA delivery

A series of multi-walled carbon nanotube (MWCNT) conjugates is described, functionalized with different dendrons bearing positive charges at their termini (i.e. ammonium or guanidinium groups). The dendrimeric units are anchored to the nanotube scaffolds using two orthogonal synthetic approaches, amidation and click reactions. The final nanohybrids are characterized by complementary analytical techniques, while their ability to interact with siRNA is investigated by means of agarose gel electrophoresis. The demonstration of the cell uptake capacity, the low cytotoxicity, and the ability of these cationic conjugates to silence cytotoxic genes suggests them to be promising carriers for genetic material. Carbon nanotubes functionalized by amidation or click chemistry with dendrons of different generations possessing ammonium or guanidinium groups are synthesized and complexed to siRNA. The assessment of the cell uptake capacity, the low cytotoxicity, and the ability of these cationic conjugates to silence genes shows them to be promising carriers for genetic material. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.