ABSTRACT
Antisense oligonucleotides (ONs) displaying base sequences complementary to a specific RNA are able to modulate selectively the expression of an individual gene (Helene and Toulme, 1990; Zon, 1988). Due to this mechanism of action, ONs were proposed for the treatment of several diseases such as viral infections or cancers resulting from oncogenes’ activation (Cohen, 1991; Cooke, 1992; Milligan et al., 1993; Stein and Cheng, 1993). However, crucial problems such as the poor stability of ONs versus nuclease activity in vitro and in vivo and their low intracellular penetration have not yet been solved (Loke et al., 1989; Yakubov et al., 1989). To overcome these obstacles, different delivery approaches were proposed: electropermeabilization, microinjection, chemical modifications, and particulate delivery systems.
