Extracellular vesicles—or exosomes, as they are more commonly known—continue to be a curious research focus for the scientific community. Once assumed to be waste materials secreted by cells, exosomes have recently been identified as mail carriers, serving an essential role in cell-to-cell communication by acting as delivery vehicles between cells. New research from Carnegie Mellon University and UPMC explores a new use case for exosomes: Delivering growth factors like bone morphogenetic proteins (BMPs) for bone healing.