A new handheld 3D printer that looks sort of like a packing tape dispenser can apply sheets of skin to cover large burn wounds, and its “bio ink” can accelerate the healing process, according to researchers from University of Toronto Engineering and Sunnybrook Health Sciences Centre in Toronto.

The device covers wounds with a uniform sheet of biomaterial, stripe by stripe. The bio ink dispensed by the roller is composed of mesenchymal stroma cells (MSCs) — stem cells that differentiate into specialized cell types depending on their environment. In this case, the MSC material promotes skin regeneration and reduces scarring. Successful in vivo trials on full-thickness wounds are reported in the journal Biofabrication.

The paper is a major step forward for the team of researchers, which unveiled the first prototype of the skin printer in 2018, according to an article on the University of Toronto Engineering News website. The device was believed to be the first of its kind to form tissue in situ, depositing and setting in place in two minutes or less. “Previously, we proved that we could deposit cells onto a burn, but there wasn’t any proof that there were any wound-healing benefits. Now we’ve demonstrated that,” said Axel Guenther, professor of mechanical and industrial engineering, who is supervising the project led by Richard Cheng, PhD candidate at the Institute of Biomaterials & Biomedical Engineering. They are working in close collaboration with Dr. Marc Jeschke, director of the Ross Tilley Burn Centre, and his team at Sunnybrook Hospital.

The current method of care for burns is autologous skin grafting, which requires transplantation of healthy skin from other parts of the body onto the wound. But large, full-body burns pose a greater challenge. Full-thickness burns are characterized by the destruction of both the outermost and innermost layers of the skin; these burns often cover a significant portion of the body. “With big burns, you don’t have sufficient healthy skin available, which could lead to patient deaths,” Jeschke told Liz Do, who authored the article on the university's website.

Since 2018, the handheld 3D printer has gone through 10 redesigns, as the team moves toward a design they envision surgeons using in an operating room. The current prototype includes a single-use microfluidic printhead to ensure sterilization, and a soft wheel that follows the track of the printhead, allowing for better control for wider wounds.

Next, Cheng says that they ultimately want to “further reduce the amount of scarring, on top of helping with wound healing. Our main focus moving forward will be on the in vivo side.”

Jeschke told Do that he believes the handheld skin printer could be seen in a clinical setting within the next five years. “Once it’s used in an operating room, I think this printer will be a game changer in saving lives. With a device like this, it could change the entirety of how we practice burn and trauma care.”