Fig. 1.

A schematic illustration showing methods used for active targeting of nanoparticles. I Antibody-based targeting, which involves the use of A monoclonal antibodies such as anti-Her2/neu antibody directed toward Her2/neu receptors on the target cell membrane, (B)antibody fragments: single-chain variable fragments (scFV) such as single-chain anti-epidermal growth factor receptor (EGFR) antibody directed toward EGFR, or antigen-binding fragment (Fab) such as anti-Her2/neu Fab. II Aptamer-based targeting such as the A10 RNA aptamer directed toward prostate-specific membrane antigen (PSMA) on the surface of the target cells. III Ligand-based targeting such as (A)transferrin-based targeting of nanoparticles toward transferrin receptors where uptake of the nanoparticles takes place through receptor-mediated endocytosis through clathrin-coated pits, (B) folate-based targeting using folic acid to target folate receptor alpha (FRα), which is upregulated on the surface of neoplastic cells