As they grow, solid tumors surround themselves with a thick, hard-to-penetrate wall of molecular defenses. Getting drugs past that barricade is notoriously difficult. Now, scientists have developed nanoparticles that can break down the physical barriers around tumors to reach cancer cells. Once inside, the nanoparticles release their payload: a gene editing system that alters DNA inside the tumor, blocking its growth and activating the immune system. Source: Science Daily/UT Southwestern Medical Center