3D-printed 'hyperelastic bone' could be the future of reconstructive surgery

Performing a bone implantation surgery has never been simple. In majority of cases, the bone is extracted from elsewhere in the body to replace the missing piece. This might result in other complications or painful infection. While adults can occasionally be given a metallic implant, such fix cannot be applied to growing children. However, engineers from Northwestern University developed a 3-D printable ink that produces a synthetic bone implant which could revolutionize reconstructive surgery.
Dubbed the ‘hyperelastic bone (HB)’, this printed biomaterial is mostly made of a mineral called hydroxyapatite – a form of calcium naturally found in bones. Described to be extremely brittle to work with, the scientists mixed it with a polymer for additional flexibility. Given its structure, it bears one significant advantage over the traditional way of bone implant surgery – it can be tailored to individual pacients. The hyperelastic bone can be easily molded, shaped or cut during a procedure to exactly fit the area where it is needed. Not only is this faster, but also less painful.
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Hyperelastic bone can be 3D-printed to make surgical implants tailored to the individual. (Source: Adam Jakus)

The synthetic bone implant comprises natural minerals and is highly porous and absorbent. Porosity is particularly important to encourage the growth of blood vessels in the 3D-printed scaffolds.
While the hyperelastic bone hasn’t been tested in humans yet, early experiments done on animals shown great promise. One of the experiment involved using the HB to fuse two vertebrae together in the spine of a rat, as The Verge reports. In another one, the scientists actually placed human stem cells on the scaffolds, resulting in the cells not only growing on the scaffolds, but also producing their own bone minerals.

“We can incorporate antibiotics [since the 3D printing process of HB can be performed at room temperature] to reduce the possibility of infection after surgery,” said Ramille N. Shah, who led the research. “We also can combine the ink with different types of growth factors, if needed, to further enhance regeneration. It’s really a multi-functional material.”

Hyperelastic bone is much more flexible than traditional materials. (Source: Adam Jakus)

According to Adam E. Jakus, a postdoctoral fellow in Shah’s laboratory, and the paper‘s first author, the hyperelastic bone could really be ideal for developing countries. It is cheap to manufacture and easy to package and ship. That would eliminate the need of creating any complex biomaterial on the spot, which would require to be heavily refrigerated or frozen.
Shah imagines that hospitals may one day have 3-D printers, where they can print customized implants while the patient waits. “The turnaround time for an implant that’s specialized for a customer could be within 24 hours,” Shah said. “That could change the world of craniofacial and orthopaedic surgery, and, I hope, will improve patient outcomes.” Before any of that can happen, it obviously has to be tested in humans first. Shah hopes to do that within five years.