Targeted lipoplexes for siRNA delivery.

RNA interference provides a powerful technology for silencing any single protein within a target cell. Therapeutic applications of small interfering RNAs (siRNAs), however, require vehicles for stable and efficient delivery of these nucleic acid molecules, both in vitro and in vivo. Targeted lipoplexes have been used as a promising system to mediate siRNA delivery and to achieve gene silencing. Electrostatic association of transferrin (Tf) to cationic liposomes enhances the transfection of siRNA. We describe the methods used for the preparation of Tf-lipoplexes and evaluation of their biocompatibility. Approaches to assess the complexation of siRNAs, the ability of Tf-lipoplexes to mediate siRNA protection, and intracellular delivery, as well as to achieve both mRNA and protein knockdown, are also described. We illustrate the efficiency of Tf-lipoplexes in mediating the knockdown of both green fluorescent protein (GFP) and luciferase in cell lines stably expressing these reporter genes.