Figure 2.

Combination strategy for drug targeting to a solid tumor using nanoparticles (NPs): after entering the systemic circulation, NPs are passively targeted and accumulated in the target tumor site by virtue of the enhanced permeability and retention (EPR) effect. Active targeting is achieved by decorating the surface of NPs with a targeting moiety and by capitalizing the advantages of aberrantly expressed receptors on the surface of tumor cells and EPR effects, resulting in improved drug delivery through receptor-mediated endocytosis.