Particularly suited to fractures that will not heal, damage caused by osteoporosis and bone diseases, the technique works by stimulating stem cells to regenerate bone directly in the affected area.
Currently, difficult injuries such as these are primarily treated by grafting healthy bone into the area, but this is invasive, painful and carries the risk of infection, and can be especially difficult if the patient has a skeletal disorder that reduces the amount of healthy bone available for grafting. Stem cells are an obvious option, but encouraging them to differentiate into bone cells in large enough quantities has proved problematic.
The new research, led by James Henstock of Keele’s Research Institute for Science and Technology in Medicine, used chicken foetal femurs and tissue-engineered collagen hydrogels to model injured bone. “We coated magnetic nanoparticles with specific targeting proteins then controlled them remotely with an external magnetic field to simulate exercise,’ Henstock explained. The nanoparticles released a protein growth stimulant in several stages once in place, resulting in an increase in bone formation and density without causing mechanical stress to either the forming bone or to the surrounding tissues, the team claims.
‘Injectable therapies for regenerative medicine show great potential as a minimally invasive route for introducing therapeutic stem cells, drug delivery vehicles and biomaterials efficiently to wound sites,’ Henstock commented. ‘This work demonstrates that providing the appropriate mechanical cues in conjunction with controlled release of growth factors to these injectable cell therapies can have a significant impact on improving bone growth.’