Hidden within our bones, marrow sustains life by producing billions of blood cells daily, from oxygen-carrying red cells to immune-boosting white cells. This vital function is often disrupted in cancer patients undergoing chemotherapy or radiation, which can damage the marrow and lead to dangerously low white cell counts, leaving patients vulnerable to infection.

The team’s new device is a small plastic chip whose specially designed chambers are filled with human blood stem cells and the surrounding support cells with which they interact in a hydrogel to mimic the intricate process of bone marrow development in the human embryo. This biologically inspired platform makes it possible to build living human marrow tissue that can generate functional human blood cells and release them into culture media flowing in engineered capillary blood vessels.

The bone marrow-on-a-chip allows researchers to simulate and study common side effects of medical treatments, such as radiotherapy and chemotherapy for cancer patients. When connected to another device, it can even model how the bone marrow communicates with other organs, like the lungs, to protect them from infections and other potentially life-threatening conditions.