ABSTRACT
Although small therapeutic agents can usually be transported passively or actively into the cells depending on their polarity and transporter availability, genes, ODNs, or siRNAs have limited permeability owing to their relatively larger size and possession of negative charges that can electrostatically repel the same charges present on cell membrane. Since small drugs generally lack sufcient specicity for their targets, distribution of such molecules to other organs apart from the target one might cause various side effects. In the case of cytotoxic drugs, nontargeted delivery as seen in traditional chemotherapy results in adverse effects on the body. Selective delivery of the small drugs to their target organs using ligandanchored nanoparticles would enable recognition of specic receptors on the target cells before the endocytosis of the complexes and cytosolic release of the drugs, thus presenting an attractive approach to eliminate (or reduce) the off-target effects and enhance the therapeutic efcacy.
