Human-like parts have been grown on the backs of mice using 3D printing. The technique could potentially be used to construct new parts or other body parts in people without the need for surgery.
It's getting more common to see customized body parts, like jaws, ribs and spinal vertebrae built by 3D printing. But these parts must be printed outside the body before they are implanted through surgery, which carries an infection risk.
Now, Mailing Gou at Sichuan University, China, and his colleagues have shown that body ports can be 3D printed inside the body, at least in mice, without the need for surgery.
Initially, the researchers injected a “bio-ink” made of hydrogel particles and cartilage cells into the backs of mice. Next, the bio-inks were exposed to the ear-shaped patterns of near-infrared light. This critical step allowed the hydrogel particles to stick together and develop layer-by-layer into parts-shaped structures. Over the next month, the cartilage cells grew around the hydrogel structures, eventually creating structure similar to the cartilage structures of real human cars. Throughout the process, the mice experienced no significant side effects.
The famous Vacanti mouse of the 1990s also had a human-like ear grown on its back, but it was made by implanting a pre-made plastic structure seeded with cartilage cells underneath the skin, rather than 3D printing the structure directly at the site.
The researchers hope the new technique could be used to construct new ears for people born with microtia, a condition that prevents the parts from developing properly. “We are making effort improve this technique for future treatment of human ear defects,” says Gou.
The nonsurgical 3D printing technique could also potentially be used to repair damaged cartilage in noses, fingers, toes or elbows, says Derek Rosenzweig at McGill University in Canada. In contrast, hip and deep knee cartilage defects may be harder to fix, because near-infrared light usually only penetrates about 2 centimeters into the body, he says.
Gou’s team hopes to eventually adapt the technique to fix other damaged organs like the heart or lungs. However, “this will be more challenging because the heart and lungs contain multiple cell types, which are deeper in the body and are constantly contracting and relaxing,” says Rosenzweig.
【小题1】What is special about the new 3D technique?| A．It requires new surgical methods. | B．It causes unexpected side effects. |
| C．It produces many customized body parts. | D．It allows new body parts to grow in the body. |
| A．The hydrogel particles. | B．The cartilage cells. |
| C．The near-infrared light. | D．The pre-made plastic structure. |
| A．It's life-saving. | B．It needs improving. |
| C．It’s still impossible. | D．It’s getting common. |
| A．New Method of Constructing Body Parts. | B．A Breakthrough in Treating Body Defects. |
| C．A New Technique Requiring No Surgery. | D．Body Parts Can Be 3D-Printed Inside the Body. |
