Inside a lab in Toronto, researchers are testing a device that looks a little like a dispenser for packing tape–but instead of tape, it lays down thin, squishy strips of 3D-printed skin. For someone with a deep cut, the type of wound that typically requires a skin graft today, the device could eventually be used to print new skin directly onto the patient.
“It forms the tissue right above the wound,” says Axel Günther, an engineering professor at the University of Toronto and one of the authors of a new paper about the technology published in the journal Lab on a Chip. The machine prints a “bio-ink” gel filled with skin cells, collagen, and fibrin, a protein that helps heal wounds.
Researchers have been developing systems that 3D print tissue for several years. Instead of extruding plastic filament, these machines can print gel with living cells. In past experiments, the fragile tissue was difficult to transfer to the skin, and the equipment hasn’t been practical for use in operating rooms.
“If you target clinical applications, the whole printer basically scales to the size of the object you’re printing, so ultimately it’s the size of a person,” Günther says. After spending time in an operating room, he realized that the device needed to be simple. “It needs to be portable. It cannot be a sort of gigantic printing machine on top of the operating table.”
When the new device prints over a deep wound, it can set in place within two minutes. Skin grafts–which involve transplanting healthy skin over deep wounds–often can’t cover an entire wound because not enough skin is available. But the printer could fully cover wounds, helping the skin better heal and protecting the patient from infections.
Günther envisions a business model similar to a regular printer and ink cartridges. “You have the handheld instrument that can be sterilized, and then you have these custom cartridges that are single use and in touch with the patient, and they can be scalably manufactured,” he says. “So instead of having one bulky instrument that’s really expensive, you have a much less expensive type of instrument, you just order more of these cartridges.”
The research is still in early stages and will involve more animal testing before it can move to human trials. One challenge is having enough skin cells available to print, since it takes time to grow cells; the researchers are working on a structure that uses as few cells as possible. The device could eventually also use “universal donor” stem cells if they become available through other research. This type of stem cell could be mass-produced and wouldn’t be rejected by individuals.
“In the event that something like that was possible and safe, that would be highly compatible with this technology–prefill the cartridges, and then centrally ship them out to hospitals,” he says. “The hospitals would not really need to have highly specialized cell manufacturing capabilities. But we’re not there yet.”