Researchers at Rensselaer Polytechnic Institute hope to develop what they call bone spackle, an engineered tissue that may help bone injuries heal faster and stronger. The idea is to devise engineered bone cells that can directly inject into an injury site. In the form of a paste, the cells could be spread onto the ends of fractured bones or used to fill in a crack.

The idea is to devise engineered bone cells that can directly inject into an injury site. In the form of a paste, the cells could be spread onto the ends of fractured bones or used to fill in a crack.

The effort starts with adult human mesenchymal stem cells (hMSC) which have the potential to become one of three forms of connective tissue -- bone, cartilage, or fat. The adult stem cells are extracted from banked bone marrow samples and grown in the Rensselaer biology lab. Chemicals in culture dishes have been the typical way of stimulating hMSC to differentiate into bone. However, in the body these chemicals can cause problems such as liver toxicity, immune-system disorders, and infection.

Researchers at Rensselaer are trying to develop bone reliably from stem cells without such chemicals. A protein called focal adhesion kinase (FAK) shows promise for signaling stem cells to become bone at an early stage. Researchers also want to learn to recognize when stem cells begin to transform into bone.Rensselaer recently got a four-year, $2.6-million grant from the National Institutes of Health to continue studying this method.