A multidisciplinary team from NYU’s Medicine and Dentistry colleges has developed 3D-printed implants that promote bone growth.

bone growth
Three-dimensional imaging on the left shows how bone, in green, replaced the bioactive ceramic scaffold, in purple, over a six-month period (Credit: Journal of Tissue Engineering and Regenerative Medicine)

Described in the Journal of Tissue Engineering and Regenerative Medicine, the implants function as bioactive scaffolds. Gel-like beta tricalcium phosphate is first printed in forms resembling the bone segments doctors want to encourage. The gel, which contains similar compounds to those found in real bone, is then superheated to create a ceramic implant.   

“Our three-dimensional scaffold represents the best implant in development because of its ability to regenerate real bone,” said senior investigator and biomedical engineer Paulo G Coelho, who works across NYU’s dentistry and medical schools. “Our latest study results move us closer to clinical trials and potential bone implants for children living with skull deformations since birth, as well as for veterans seeking to repair damaged limbs.”

Once implanted in a subject, the ceramics act as a template for real bone to form around. However, their composition means they resorb over time, gradually breaking down to leave just new bone. One of the keys to the rapid growth of native bone is a coating of dipyridamole on the implants, a blood thinner shown in other experiments to speed up bone formation by more than 50 per cent. Dipyridamole also attracts bone stem cells, which spur the formation of nourishing blood vessels and bone marrow within the newly grown bone. According to the researchers, these soft tissues give the scaffold-grown bone the same flexibility as natural bone.

“Dipyridamole has proven to be key to the implant’s success,” said study co-investigator Bruce N Cronstein, a professor at NYU School of Medicine. “And because the implant is gradually resorbed, the drug is released a little at a time and locally into the bone, not into the whole body, thereby minimising risks of abnormal bone growth, bleeding, or other side effects.”

The team has so far successfully tested the implants on mice and rabbits and has plans to carry out further testing on larger mammals. Clinical trials, however, are likely several years away.

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