Growing Bone – A Moonshot Project

Molly Stevens uses chemistry, mechanics and material science to regenerate bone tissue.

Molly Stevens finds inspiration in historical medicine. She explains how the Mayans used the blue nacre shell as an artificial tooth replacement, and Sir Harold Ridley observed Spitfire pilots in World War II to create lenses that combat cataracts. These examples led her to look for medical advances that are bio-inert in the body, even though she felt the medical field was moving toward bio-active materials.

 In her TED Talk Molly Stevens: A new way to grow bone, Stevens explains the methods and materials behind her bone regeneration ideas.

Bone tissue is good at repairing itself, and in the US there are around one million defects per year that require some kind of bone grafting. The drawbacks to this method are massive pain when transferring bone, and a limited supply of bone in the body.

Stevens and her team worked to find a way to force the bone to regenerate itself on demand. Her method is call the in vivo bioreactor, and uses a liquid injection to create an artificial cavity in the bone. The cavity begins a reaction that causes stem cells to push bone tissue growth.

Border between the new bone and old bone is weak, allowing for surgeons to harvest the new bone tissue with limited pain to the patient. The process also allows for healthy bone tissue, usually in the leg, to grow new healthy tissue for other parts of the body.

Developing the chemical makeup of the gel has allowed Stevens to dictate how much of the tissue is bone vs. cartilage. Using the macro vs nano properties of bone tissues the team has created flexible spongy material and also hard brittle material.

One long term goal of this research is to apply the tissue regeneration to cardiovascular research. Cardio cells often need to be more conductive than bone so the work has a higher level of complexity.