Cell penetrating peptide-mediated systemic siRNA delivery to the liver.

The cell-penetrating peptide (CPP) is one of the most attractive tools for efficiently delivering biomolecules to a target organelle. Here, we describe the use of octaarginine (R8)-modified lipid nanoparticles for the efficient and targeted in vivo delivery of siRNA to the liver. In this study, SR-BI (a scavenger receptor class B, member 1) was targeted by this nanoparticle. Our results demonstrate that R8-modified lipid nanoparticles can be used for the efficient and targeted delivery of liver siRNA to induce the specific knock-down of an endogenous gene with minimum liver toxicity and immune response, and that this CPP based technology holds considerable promise for further in vivo biological applications of siRNA.