EXACT replicas of a man's thumb bones have been made for the first time using a 3D printer. The breakthrough paves the way for surgeons to replace damaged or diseased bones with identical copies built from the patients' own cells.
"In theory, you could do any bone," says Christian Weinand of the Insel Hospital in Berne, Switzerland, head of the team that copied his thumb bones. "Now I can put spares in my pocket if I want," he says.
Weinand "grew" his replacement bones on the backs of laboratory mice, in the same way that Jay Vacanti of Massachusetts General Hospital famously grew a human ear from human cartilage cells back in 1997.
However, a surrogate mouse would normally be unnecessary, says Weinand. For example, if someone had lost a thumb, the replacement bones could be grown in situ. For now, the only options are to replace the thumb with the patient's own toe, or with bone fragments from elsewhere.
There are several steps in the new process. Firstly, you need a 3D image of the bone you want to copy. If the bone has been lost or destroyed, you can make a mirror image of its surviving twin.
This image is then fed into a 3D inkjet printer, which deposits thin layers of a pre-selected material on top of one another until a 3D object materialises.
Weinand loaded the printer with tricalcium phosphate and a type of polylactic acid - natural structural materials found in the human body. The resulting bone "scaffolds" contained thousands of tiny pores into which bone cells could settle, grow and eventually displace the biodegradable scaffold altogether.
Thumbs up for 3D bone printer
