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Updated: Feb 6, 2026

Delivery of Therapeutic siRNA to the CNS Using Cationic and Anionic Liposomes
Published on: July 23, 2016
Enhanced Intercellular Delivery of cRGD-siRNA Conjugates by an Additional Oligospermine Modification
Kosuke Nakamoto1, Yukihiro Akao1, Yasuhiro Furuichi2
1United Graduate School of Agricultural Science, United Graduate School of Drug Discovery and Medical Information Sciences, and Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Abstract:
Small interfering RNA (siRNA), consisting a 21-mer duplex molecule, is often modified by conjugation with specific ligands to enhance its capacity for tissue-specific delivery. However, these attempts are hampered by the low permeability of negatively charged RNA molecules to enter the cell membrane. In this study, we designed and synthesized siRNA conjugates modified with cationic oligospermine and cyclic RGD (cRGD) to overcome the low-membrane permeability of siRNA. The siRNA conjugate, which contains 15 spermines and a cRGD peptide, showed sufficient gene-silencing activity at 250 nM final concentration without a transfection reagent. Under these conditions, the cationic oligospermine and cRGD-siRNA conjugate did not show any cytotoxicity.
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