Extracellular vesicles (EVs; article here) are one of the biggest stories in biology. These tiny "packets" are released by cells and constitute a previously misunderstood means of intracellular communication -- and their implications are huge. In humans, EVs can reveal disease, including some cancers and viral infections, and EV technology may soon replace many tissue biopsies. In addition, vesicles can be loaded with targeted treatments for a variety of diseases. The role that EVs will play in medicine is only beginning to be understood. In this episode, I'm joined by Drs. Xandra Breakefield and Mikolaj Zaborowski, two Harvard Medical School researchers working at the forefront of the field.