American scientists have developed a hybrid printer that prints cartilage, which could one day be implanted into injured patients to help re-grow cartilage in areas such as the joints.

The 3D tissue printer, featured in a study published in the journal Biofabrication by the Institute of Physics, is a mix of a traditional ink jet printer and an electrospinning machine.

In this study, done by scientists at Wake Forest University in North Carolina, the hybrid system produced cartilage with better mechanical stability than those created by an ink jet printer.

“This is a proof of concept study and illustrates that a combination of materials and fabrication methods generates durable implantable constructs,” said Dr. James Yoo, a professor at the Wake Forest Institute for Regenerative Medicine, and an author on the study.

Other methods of making cartilage, such as robotic systems, are also being developed to improve implantable tissue.

Key to the success of the hybrid printer is the electrospinning machine, which can generate very fine fibres from a polymer solution. The polymers can be easily controlled and made porous, which is important in getting real cartilage cells to integrate into the surrounding tissue.

Researchers built cartilage by combining electrospun polymer with cartilage cells from a rabbit’s ear that were deposited using the traditional ink jet printer. The cartilage was tested on mice and after eight weeks it had developed the structures and properties of real cartilage, demonstrating its potential use in humans.

In future, researchers say clinicians could develop cartilage specific to the needs of patients. For instance, an MRI scan of the body part, such as the knee, would provide a sort of blueprint and then matching cartilage could be created.