Aptamer mediated siRNA delivery

Nucleic acids that bind to cells and are sub- sequently internalized could prove to be novel deliv- ery reagents. An anti-prostate specific membrane antigen aptamer that has previously been shown to bind to prostate tumor cells was coupled to siRNAs via a modular streptavidin bridge. The resulting conjugates could be simply added onto cells with- out any further preparation, and were taken up within 30 min. The siRNA-mediated inhibition of gene expression was as efficient as observed with conventional lipid-based reagents, and was depend- ent upon conjugation to the aptamer. These results suggest new venues for the therapeutic delivery of siRNAs and for the development of reagents that can be used to probe cellular physiology.