A new “organ on a chip” has been developed by Harvard researchers, reproducing the structure, functions, and cellular make-up of bone marrow, a complex tissue that until now, could only be studied on living animals.

Microscopic view of the engineered bone with an opening exposing the internal trabecular bony network, overlaid with colored images of blood cells and a supportive vascular network that fill the open spaces in the bone marrow-on-a-chip (credit: James Weaver/Harvard’s Wyss Institute)

Bone marrow is one of the more complex and fragile parts of the human body – many drugs and toxic elements affect the bone marrow in ways that are hard to predict, and hard to study. Until now, the only reason to do this was to study it on living animals, something which, needless to say, is costly, unpleasant, and risky. But now, scientists from Harvard’s Wyss Institute for Biologically Inspired Engineering have developed what they call “bone marrow-on-a-chip”, a device which could be used to develop safe and effective strategies to prevent or treat radiation’s lethal effects on bone marrow without resorting to animal testing.

The main focus of such studies is cancer treatment – many such treatments such as radiation therapy or high-dose chemotherapy are hazardous for bone marrow. Animal testing is not really efficient for studying such matters, and it also raises some moral issues.

“Bone marrow is an incredibly complex organ that is responsible for producing all of the blood cell types of our body, and our bone marrow chips are able to recapitulate this complexity in its entirety and maintain it in a functional form in vitro ,” said Don Ingber, M.D., Ph.D., Founding Director of the Wyss Institute, Judah Folkman Professor of Vascular Biology at Harvard Medical School and Boston Children’s Hospital, Professor of Bioengineering at SEAS, and senior author of the paper.

Ingber leads a larger initiative to develop more “organs on a chip” – small microfluidic devices that mimic the physiology of living organs. So far, they’ve developed lung, heart, kidney, and gut chips that reproduce key aspects of organ function, and have more in the works. In order to build them, they combine multiple types of cells from an organ on a microfluidic chip, while steadily supplying nutrients, removing waste, and applying mechanical forces that the organ would naturally encounter in the human body.

The researchers report the development in the May 4, 2014 online issue of Nature Methods.