April 28 (UPI) -- Researchers at Sahlgrenska Academy at the University of Gothenburg in Sweden have successfully generated cartilage tissue by printing stem cells using a 3D bioprinter.
The researchers were able to create the cartilage tissue by harvesting cartilage cells from patients who had knee surgery. The cells were then manipulated by researchers, causing them to rejuvenate and revert into pluripotent stem cells.
The stem cells were expanded and encapsulated in a composition of nanofibrillated cellulose, and then printed into a structure using a 3D bioprinter. The stem cells were then treated with growth factors, causing them to differentiate properly and form cartilage tissue.
"We investigated various methods and combined different growth factors," Stina Simonsson, an associate professor of cell biology at Sahlgrenska Academy, said in a press release. "Each individual stem cell is encased in nanocellulose, which allows it to survive the process of being printed into a 3D structure. 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."
The 3D-printed cartilage formed by the stem cells is very similar to human cartilage, and surgeons who compared the artificial cartilage to real cartilage saw no difference between them. The lab-grown cartilage also contains Type II collagen and appears to have structures similar to human-harvested cartilage when examined under a microscope.
The 3-bioprinted cartilage could be used to repair cartilage damage or treat osteoarthritis, the researchers say.
"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, the most important thing for use in a clinical setting is safety."
The study was published in Scientific Reports.