Researchers have developed a new artificial bone that could become the next breakthrough in reconstructive surgery.
The new material called hyperelastic bone is shaped using a 3D printer and acts like a natural bone in the body. It can help repair or regenerate broken bones as well as some other forms of injury.
Surgeons use the naturally occurring mineral hydroxyapatite to repair damaged bones. Because it is a major component and essential ingredient of human bones, hydroxyapatite blends well with the body's natural tissue and allows cells to grow.
Hydroxyapatite, however, is very brittle. It is also very stiff, which makes it difficult for doctors to work with. The newly developed hyperelastic bone, which was described in the study published in the journal Science Translational Medicine on Sept. 28, offers a solution to the tricky nature of this mineral.
Study researcher Ramille Shah and colleagues from Northwestern University developed the hyperelastic bone material by mixing hydroxyapatite and a biodegradable polymer producing a more flexible biomaterial. The resulting hyperelastic bone material is then tested in experiments.
The researchers placed humans stem cells into scaffolds that were 3D printed from the hyperelastic bone material. They found that the cells did not only grow without any problem on the scaffolds, but it filled up the available space in just a few weeks. The stem cells also transformed into bone cells.
"Cells can sense the hydroxyapatite and respond to its bioactivity," Shah said. "When you put stem cells on our scaffolds, they turn into bone cells and start to up-regulate their expression of bone specific genes. This is in the absence of any other osteo-inducing substances. It's just the interaction between the cells and the material itself."
The researchers attribute the success of the material to its unique properties. While it is mainly composed of the brittle hydroxyapatite, it is hyperelastic, robust and porous.
"[W]e generated a new, synthetic osteoregenerative biomaterial, hyperelastic 'bone' (HB)," the researchers reported in their study.
"The resulting 3D-printed HB exhibited elastic mechanical properties (~32 to 67 percent strain to failure, ~4 to 11 MPa elastic modulus), was highly absorbent (50 percent material porosity), supported cell viability and proliferation, and induced osteogenic differentiation of bone marrow-derived human mesenchymal stem cells cultured in vitro over four weeks without any osteo-inducing factors in the medium."
Because the material is easy to cut and shape, it can be used for tailor-made implants based on a patient's MRI and other scans.
