When Adam Jakus was a postdoc at Northwestern University he accidentally spilled some “ink” he'd created from powdered ovaries intended for 3-D printing. Before he could wipe up the mess, it solidified into a thin, paper-like sheet, reports Charles Q. Choi at LiveScience. That led to a lab-bench epiphany.
“When I tried to pick it up, it felt strong,” Jakus says in a press release. “I knew right then I could make large amounts of bioactive materials from other organs. The light bulb went on in my head.”
Jakus, along with the same team that developed a 3-D printed mouse ovary earlier this year, began experimenting with the concept. According to a video, they began collecting pig and cow organs from a local butcher shop, including livers, kidneys, ovaries, uteruses, hearts and muscle tissue.
The team then used a solution to strip the cells from the tissues, leaving behind a the scaffolding material of collagen proteins and carbohydrates. After freeze-drying the matrix, they powdered it and mixed it with materials that allowed them to form it into thin sheets. The research appears in the journal Advanced Functional Materials.
“We’ve created a material we call 'tissue papers' that’s very thin, like phyllo dough, made up of biological tissues and organs,” says Ramille Shah, head of the lab where the research took place, in the video. “We can switch out the tissue we use to make the tissue paper—whether that be derived from liver or muscle or even ovary. We can switch it out very easily and make a paper out of any tissue or organ.”
According to the press release, the material is very paper-like and can be stacked in sheets. Jakus even folded some into origami cranes. But the tissue paper’s most important property is that it is biocompatible and allows for cellular growth. For instance, the team seeded the paper with stem cells, which attached to the matrix and grew over four weeks.
That means the material could potentially be useful in surgery, since paper made of muscle tissue could be used as a sophisticated Band-Aid to repair injured organs. “They're easy to store, fold, roll, suture and cut, like paper," Jakus tells Choi. “Their flat, flexible nature is important if doctors want to shape and manipulate them in surgical situations.”
Northwestern reproductive scientist Teresa Woodruff was also able to grow ovary tissue from cows on the paper, which eventually began producing hormones. In the press release, she explains that a strip of the hormone-producing tissue paper could be implanted, possibly under the arm, of girls who have lost their ovaries due to cancer treatments to help them reach puberty.
The idea of using extracellular matrices, hydrogels or other material as a scaffolding to bioprint organs like hearts and kidneys is being investigated by labs around the world. In 2015, a Russian team claimed they printed a functional mouse thyroid. And this past April, researchers were able to bioprint a patch derived from human heart tissue that they used to repair the heart of a mouse.