Carnegie Mellon University's

Bone Tissue Engineering Initiative 

Tissue Engineering is a multidisciplinary/interdisciplinary field that applies the principles of biology and engineering to develop tissue substitutes to restore, maintain, or improve the function of diseased or damaged human tissues. (Please visit our tissue engineering tutorial for more background information). One approach for engineering tissue involves seeding biodegradable scaffolds with donor cells and/or growth factors, then culturing and implanting the scaffolds to induce and direct the growth of new, healthy tissue. Examples of tissue engineered substitutes that are currently being investigated throughout the world include skin, cartilage, bone, vasculature, heart, breast, and liver.

The need for bone substitutes is particularly important. Bone substitutes are often required to help repair or replace damaged or diseased tissues in cases ranging from trauma, to congenital and degenerative diseases, to cancer, to cosmetics. There are approximately 500,000 surgical procedures performed every year in the U.S. which require bone substitutes. Currently available bone substitutes, including autografts, allografts, and synthetic materials, are the most implanted materials second only to transfused blood products. However, these substitutes are from ideal and have many associated problems, e.g., autografting is expensive and can have significant donor site morbidity, and synthetic materials wear and do not behave like true bone. Our goal is to provide an alternative solution by creating large-scale, tissue engineered bone.
 
Our Vision for creating tissue engineered bone is an advanced CAD/CAM (computer-aided-design / computer-aided-manufacturing) bioreactor system capable of growing large-scale, customized bone substitutes as depicted in the figure above. A CAD model of the desired bone substitute would first be derived from CAT or MRI data of the patient. The synthetic bone would then be fabricated, in-vitro, in an advanced CAM bioreactor by depositing layers of biodegradable scaffolding material while simultaneously embedding donor cells and growth factors within the layers. Synthetic vasculature would also be embedded within the scaffold as it is being built up. The scaffold structure, cellular distributions, and growth factor concentrations would be spatially varied using selective deposition. Additional osteogenic cues, such as mechanical stimulus, would be provided until the tissue was mature enough to be removed from the bioreactor and implanted into the patient. Such a system would also have applicability to other tissues and whole organs.

Our current research involves not only laying the foundation for several of the components required for realizing such an advanced system, but also gaining knowledge and developing components that will have clinical relevance in the nearer term. Our current projects include:

  1. Scaffold Materials
  2. Solid Freeform Fabrication of Scaffolds
  3. Synthetic Vessels
  4. Growth Factors

Our research group is a multidisciplinary/interdisciplinary team from The Robotics Institute and The Institute for Complex Engineered System (ICES) of Carnegie Mellon University, and from the University of Pittsburgh Medical Center (UPMC) and School of Dental Medicine (UPSDM).

This research is sponsored, in part, by Carnegie Mellon University, The Office of Naval Research, and The Pittsburgh Tissue Engineering Initiative, and The Pennsylvania Infrastructure Technology Alliance.