Cartilage grown using algae scaffold

Cartilage has been created by a team of engineers using a 3D printer and bioink — made from living cells.

Cartilage is suitable for large scale bioprinting as it is unicellular and contains no blood vessels. The researchers have said that the printed material is similar to cow cartilage, although it’s mechanically inferior to human cartilage.

Ibrahim T. Ozbolat, associate professor of engineering science and mechanics at Penn State University, said: “Our goal is to create tissue that can be used to replace large amounts of worn out tissue or design patches. Those who have osteoarthritis in their joints suffer a lot. We need a new alternative treatment for this.”

Initially, previous attempts to grow cartilage began with cells that were embedded in a hydrogel. Composed of polymer chains and about 90% water, it was used as a scaffold to grow tissue. However, the cells grown in the gel were found to not have sufficient mechanical integrity.

Instead, researchers created tiny tubes between three and five one hundredths of an inch in diameter made of alginate. Cartilage cells were injected into the tube and grown for a week. As the cells do not stick to the alginate, they could be easily removed from the tubes.

A specially designed prototype nozzle was attached to the 3D printer, allowing for rows of cartilage strands to be printed according to the researchers’ wishes. After 30 minutes, the cells had self-adhered enough to be moved to a Petri dish containing nutrient media, where they eventually fused together.

Ozbolat said as no scaffolding is used the printing process is scalable so the patches can be made bigger. He added: “We can mimic real articular cartilage by printing strands vertically and then horizontally to mimic the natural architecture."

The study was published on Scientific Reports.