Passive Targeting Passive targeting leverages the natural properties of nanoparticles and the enhanced permeability and retention (EPR) effect. Tumor tissues often have leaky vasculature, allowing nanoparticles to accumulate more readily than in normal tissues. This strategy relies on the physical and chemical properties of the nanoparticles to achieve localization.
Active Targeting Active targeting involves modifying the surface of nanoparticles with specific ligands or antibodies that bind to receptors overexpressed on the target cells. This method enhances the precision of delivery. Common ligands include antibodies, peptides, and small molecules designed to interact with specific cellular receptors.
Stimuli-Responsive Targeting Stimuli-responsive targeting uses nanoparticles that respond to specific environmental triggers such as pH, temperature, or enzymatic activity. For instance, pH-sensitive nanoparticles can release their drug payload in the acidic environment of a tumor, ensuring that the drug is released precisely where it is needed.
