From the Lab to the Real World

Not Your Ordinary Inkjet: Researchers Develop Printers to Make Artificial Skin and Bone

Researchers at two CAHO hospitals use 3D printing to generate skin and bone replicates for severe burns and joint replacement, respectively. This new technology, still years away from large-scale use, could improve the patient’s quality of life, reduce lengths of stay and save health care dollars.

Back in 1440, Johannes Gutenberg invented the printing press, a profound technological advancement. Today, scientists are pushing printers into the realm of science fiction. Researchers at two CAHO hospitals have developed three dimensional (3D) printers that produce human-like skin and bone:  At Sunnybrook Health Sciences Centre, Dr. Marc Jeschke is helping to develop a printer that produces artificial skin to help burn patients; and at Mount Sinai Hospital, Dr. Rita Kandel has developed a system that fuses the patient’s own tissues with a bone replacement created by a 3D printer.

This new technology, for which testing is still in the early stages, could speed up the recovery process; reduce lengths of stay, which would save money for the health care system; and above all, ease pain and improve the patient’s quality of life.

Dr. Marc Jeschke   Dr. Rita Kandel
Left to right: Dr. Marc Jeschke, Sunnybrook Health Sciences Centre; and Dr. Rita Kandel, Mount Sinai Hospital, Lunenfeld-Tanenbaum Research Institute. Photographs reproduced with permission.

Printing Human-Like Skin for Burn Patients

The skin printer was invented at the University of Toronto, affiliated with Sunnybrook. Here, a team of researchers led by Dr. Axel Guenther developed a printer that looks like regular inkjet printer but produces a tissue closely resembling human skin. It’s called the Bioprinter and Guenther says that it can produce one square meter of tissue in roughly 45 minutes.

skin printer
Bioprinter: 3-D printer that produces artificial skin.

Here’s how it works: Using chemical compounds in place of ink, special solutions are fed into the computerized machine (the printer) through small wells or chambers, and the liquids are blended together. Basic ingredients include the patient’s own tissue (stem cells), calcium chloride and a form of algae, the chemical building blocks of skin. When the resulting gel-like substance is spun around a spool, generating many successive micro-layers of material, it creates fibres that serve as the skin scaffolding or netting. This netting, the artificial skin, is then collected on a drum, like paper towel on a roll, and printed out.

Sunnybrook Hopes to Move Research from Lab to Clinic

Jeschke, medical director of the Ross Tilley Burn Centre at Sunnybrook and close collaborator on the U of T project, is seeking to move this research from the lab to the clinic. “This new procedure would revolutionize modern-day approaches to burn treatment,” he says. “For the millions of people around the world who suffer burns each year, it could change the game on how we practise wound care,” he adds.

Large-scale burns typically cover 50 to 70% of the body, and severe burns can be life threatening. Many burn patients undergo multiple painful operations to graft skin from another part of their bodies or from a cadaver. But skin grafting increases the wound size, which multiplies the possibility of inflection, and lengthens recovery time.

Artificial skin
Petri dishes containing artificial skin.

Skin printing could change all this. “In the future, we may be able to add the cells of burn patients to the device and have it print out skin that is the colour of their skin, with sweat glands, hair, dermis, epidermis – mimicking their own anatomical skin,” Jeschke says. He believes that, one day, the Bioprinter could produce a whole body’s worth of skin in four to five hours.

Fanny Sie, project manager for Bioprinter, adds, “In theory, in the future, we could possibly print 3D organs.”

Testing is still in the early stages with large-scale use roughly a decade away. Guenther’s team, backed by U of T’s Connaught Fund, is currently working with MaRS Innovation in collaboration with U of T’s Innovations and Partnerships Office to find commercial applications for the printed tissue. To date, the current price tag for artificial skin is steep: $30,000 to $40,000 for a very small surface area of coverage.

Printing Artificial Bone for Joint Replacements

Across the city at Mount Sinai Hospital, Kandel’s team, which includes collaborators from a number of Ontario universities, has devised a way to print a bone replacement using a calcium phosphate compound that has many of the same properties of human bone.

Kandel, an associate scientist at Mount Sinai’s Lunenfeld-Tanenbaum Research Institute and chief of Mount Sinai’s Department of Pathology and Laboratory Medicine, sees great potential for this artificial bone in joint replacement, which is on the rise. There were 93,446 hip and knee replacements in Canada in 2010-2011—up from 82,717 four years earlier (Canadian Institute for Health Information).  Existing joint replacements, using metal or plastic parts, may require cementing to bone, can deteriorate or come loose over time, and usually needs replacing after 10 to 20 years.

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Joint replacement wherein the original damaged joint will be replaced by a joint made entirely of the patient’s own tissues.

In Kandel’s work, the bone replacement becomes the scaffolding for the replacement cartilage, which is regenerated from the patient’s stem cells. “We take the worn-out joint and use the patient’s stem cells to grow actual tissue (cartilage) on it. The original damaged joint will be replaced by a joint made entirely of the patient’s own tissues,” she says. “It’s quite extraordinary,” she adds.

The natural bone then regrows over the porous and biodegradable printed material that dissolves over time as the patient’s natural bone regrows. “The bone attaches to the cartilage that was implanted, and you completely reconstruct a normal joint using the patient’s own cells. So there are no metals or plastics, and no typical way of failure that’s found in these prostheses,” she says.

With funding from the Canadian Institutes of Health Research and the United States Army, Kandel and her team have created new knee joints for animals and hope to apply the procedure to humans in the next few years.

She sees 3D printing as a shining example of personalized medicine: “With 3D printing, we can tailor precisely the implant to the missing structure in a patient’s body.”

To read more about Kandel’s research, go to:  http://bit.ly/IqRy8d. To read more about the Bioprinter, go to: http://bit.ly/1eGyezb.