Accidents and diseases like cancer can cause people to lose parts of their bone. Today, sections of missing bone can only be replaced with bone harvested from elsewhere in the same body. However, soon doctors may be able to 3D print bone (in the form of a cell-containing gel that hardens in minutes) straight into the damaged area.
This new gel is different from existing experimental material, which can be put in a cavity where the bone is missing to serve as micro-structured scaffolding for the adjacent bone tissue to migrate into gradually. It takes time for the patients’ cells to reproduce and take over the material. But the new 3D printed gel is much faster because it already has the living bone cells in it. This faster alternative was created by scientists at Australia’s University of New South Wales-Sydney.
Assoc. Prof. Kristopher Kilian, who is co-leading the study, said:
The cool thing about our technique is you can just extrude it directly into a place where there are cells, like a cavity in a patient’s bone. We can go directly into the bone where there are cells, blood vessels and fat, and print a bone-like structure that already contains living cells right in that area. There are currently no technologies that can do that directly.
The “bio-ink” is a calcium phosphate-based non-toxic gel infused with the patients’ cells. The technique used to 3D print the bio-ink directly into the patient’s bone deficit is known as ceramic omnidirectional bioprinting in cell-suspensions (COBICS).
The gel hardens within minutes of exposure to the patient’s bodily fluids. The result is a bone-like material consisting of mechanically interlocked bone mineral nanocrystals laced with living bone cells, which reproduce and replace the material with natural bone.
Dr. Iman Roohani, the other researcher co-leading the study, said:
The ink takes advantage of a setting mechanism through the local nanocrystallisation of its components in aqueous environments, converting the inorganic ink to mechanically interlocked bone apatite nanocrystals. In other words, it forms a structure that is chemically similar to bone-building blocks. The ink is formulated in such a way that the conversion is quick, non-toxic in a biological environment, and it only initiates when ink is exposed to the body fluids, providing ample working time for the end-user, for example, surgeons.
This unique technology would be the ultimate tool in clinics that perform in situ repair of bone defects caused by cancer or trauma. It would also be useful for research and disease modeling.
Kilian added:
This advance really paves the way for numerous opportunities that we believe could prove transformational – from using the ink to create bone in the lab for disease modeling, as a bioactive material for dental restoration, to direct bone reconstruction in a patient.
I imagine a day where a patient needing a bone graft can walk into a clinic where their bone’s anatomical structure is imaged, translated to a 3D printer, and directly printed into the cavity with their own cells. This has the potential to radically change current practice, reducing patient suffering and ultimately saving lives.
Next, the researchers will see if the living cell in the bone-like constructs grows after implantation by performing in vivo tests in animal models.
Other recent achievements in the world of bio-printing include 3D printed hearts, 3D printed anti-cancer patches, 3D printed mini-liver, and bedside bioprinters that can print new skin directly into wounds.
