Swedish researchers have reported the 3D printing of cartilage tissue using stem cells. The cells survived the process and began to multiply and to form chondrocytes, or cartilage cells, in a printed structure.
Surgeons who examined the artificial said there appeared to be no difference from ordinary human tissue.
“In nature, the differentiation of stem cells into cartilage is a simple process, but it’s much more complicated to accomplish in a test tube,” team leader Stina Simonsson of the of University of Gothenburg said in a media release.
The team used cartilage cells harvested from patients who underwent knee surgery. These were made to revert into “pluripotent” stem cells – stem cells that have the potential to develop into many different types of cells.
The stem cells were encapsulated in a nano-cellulose compound and printed into a structure using a 3D bioprinter.
After printing they were treated with growth factors that caused them to differentiate correctly, so that they formed cartilage tissue.
Simonsson says the nanocellulose allows the stem cells to survive the process of being printed.
“We also harvested mediums from other cells that contain the signals that stem cells use to communicate with each other so called conditioned medium.
“In layman’s terms, our theory is that we managed to trick the cells into thinking that they aren’t alone,” she said.
While the most important finding was the procedure by which cells can survive printing, the study also shows that it is not necessary to use large amounts of live stem cells to form tissue.
The study in an important step towards the ability to generate cartilage based on a patient’s own stem cells, which can be used to repair cartilage damage, or to treat osteoarthritis.
“The structure of the cellulose we used might not be optimal for use in the human body,” Simonsson said.
“Before we begin to explore the possibility of incorporating the use of 3D bioprinted cartilage into the surgical treatment of patients, we need to find another material that can be broken down and absorbed by the body so that only the endogenous cartilage remains.”