The Enhanced Permeability and Retention (EPR) effect is a phenomenon that is crucial in the field of nanotechnology and cancer therapy. It describes the tendency of nanoparticles and macromolecules to accumulate in tumor tissue more than in normal tissues. This is primarily due to the unique characteristics of tumor blood vessels, which are often leaky and poorly organized, allowing larger particles to pass through and be retained in the tumor microenvironment.
