Linked nucleosides having at least one functionalized nucleoside that
bears a substituent such as a steroid molecule, a reporter molecule, a
non-aromatic lipophilic molecule, a reporter enzyme, a peptide, a
protein, a water soluble vitamin, a lipid soluble vitamin, an RNA
cleaving complex, a metal chelator, a porphyrin, an alkylator, a pyrene,
a hybrid photonuclease/intercalator, or an aryl azide photo-crosslinking
agent exhibit increased cellular uptake and other properties. The
substituent can be attached at the 2'-position of the functionalized
nucleoside via a linking group. If at least a portion of the remaining
liked nucleosides are 2'-deoxy-2'-fluoro, 2'-O-methoxy, 2'-O-ethoxy,
2'-O-propoxy, 2'-O-aminoalkoxy or 2'-O-allyloxy nucleosides, the
substituent can be attached via a linking group at any of the 3' or the
5' positions of the nucleoside or on the heterocyclic base of the
nucleoside or on the inter-nucleotide linkage linking the nucleoside to
an adjacent nucleoside.