Strands of cow cartilage substitute for ink in a 3D bioprinting process that may one day create cartilage patches for worn out joints, according to a team of engineers.
"Our goal is to create tissue that can be used to replace large amounts of worn out tissue or design patches," said Ibrahim T. Ozbolat, associate professor of engineering science and mechanics. "Those who have osteoarthritis in their joints suffer a lot. We need a new alternative treatment for this."
Cartilage is a good tissue to target for scale-up bioprinting because it is made up of only one cell type and has no blood vessels within the tissue. It is also a tissue that cannot repair itself. Once cartilage is damaged, it remains damaged.
Previous attempts at growing cartilage began with cells embedded in a hydrogel -- a substance composed of polymer chains and about 90 percent water -- that is used as a scaffold to grow the tissue.
"Hydrogels don't allow cells to grow as normal," said Ozbolat, who is also a member of the Penn State Huck Institutes of the Life Sciences. "The hydrogel confines the cells and doesn't allow them to communicate as they do in native tissues."
This leads to tissues that do not have sufficient mechanical integrity. Degradation of the hydrogel also can produce toxic compounds that are detrimental to cell growth.