Figure 3.

Nanoparticles (NP) types: passive and active targeting. (A) Schematic representation of different NP types: liposomes, polymeric NP, dendrimers, and micelles. Passive targeting: accumulation of a drug-driven by NP to the site of the lesion. EPR: “enhanced permeation and retention effect”, which allows NP to pass tumor vascular endothelium. (B) Active targeting: surface modifications of NP responsible for the increase of circulation half-life and selectivity of delivery. Examples of such modifications: polyethylene glycol (PEG)ylation, coating with sugars, small molecules, and peptides. FT: folate; HA: hyaluronic acid. Peptides containing sequences involved in internalization (such as RGD) improve drug uptake. Conjugation with specific therapeutic antibodies (Abs) will confer to NP high specificity of targeting.