ABSTRACT
Oligonucleotide (ON)-based therapy promises to be a highly specific tool for the treatment of numerous human diseases. However, to date the effectiveness of ONs has been limited by several problems such as instability in serum, inability to reach their target site because of non-specific disposition, poor cell penetration and adverse pharmacokinetics. These hurdles have stimulated efforts to prepare neutral or charged backbone-modified oligonucleotides, but the limitations have been only partly solved (Agrawal and Iyer, 1997).
