Artificial human body parts

Exact replicas of a man’s thumb bones have been made for the first time
using a printer that uses natural materials for ink

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.

Source: “Thumbs up for 3D bone printer”, New Scientist.

The smooth cartilage that covers the ends of long bones provides a level of lubrication that artificial alternatives haven’t been able to rival – until now. Researchers say their lubricating layers of “molecular brushes” can outperform nature under the highest pressures encountered within joints, with potentially important implications for joint replacement surgery.

With every step we take, bones at the knee and hip rub against each other. That would quickly wear them away if it wasn’t for the protection afforded by the thick layer of smooth and slippery cartilage that covers their ends.

No amount of polishing can remove all of the small imperfections from the stainless steel used in artificial joints. Any raised areas that are left grind against each other and release debris particles that soften the bone, explains Jacob Klein at the Weizmann Institute of Science in Rehovot, Israel.

Like bone, artificial joints must be covered with a cartilage-like layer. However, while it’s possible to match cartilage’s slick properties at low pressure, at the high pressures found in joints synthetic alternatives “seize up”.

Source: “Artificial cartilage performs better than the real thing”, New Scientist.