Nanoparticles can be engineered to target specific sites through various mechanisms: 1. Passive Targeting: Utilizes the enhanced permeability and retention (EPR) effect, where nanoparticles accumulate in tumor tissues due to their leaky vasculature. 2. Active Targeting: Involves modifying the surface of nanoparticles with ligands or antibodies that bind specifically to receptors on the target cells. 3. Stimuli-Responsive Targeting: Nanoparticles are designed to respond to specific stimuli such as pH, temperature, or enzymes, releasing their payload only at the target site.
