3D Printing Skin Grafts to Heal Burns
A young team has developed a new method -- and new hardware -- for bioprinting
Global competition to perfect and patent 3D printing-based medical technology has only intensified of late, its products ranging from printed lightweight casts to body parts; participants include institutions of all sizes, and — since biotech hackers BioCurious kindly released instructions for assembling a DIY bioprinter — even amateurs. In the fight to treat burns and lesions with 3D-printed skin, the US Army has revealed itself as a major contender; as a result of a recent international competition, however, an award-winning Canadian team has just entered the ring.
University of Toronto engineering students Arianna McAllister and Lian Leng took first prize in the Canadian leg of the 2014 James Dyson Awards program with their PrintAlive Bioprinter, receiving a $3,500 prize and the chance to compete internationally with teams from 18 countries for $50,000 more. The James Dyson Foundation, a non-profit dedicated to “encouraging young people” in the engineering and scientific fields, uses its annual award program to feature students’ “industrial or product designs that solve a problem.”
The problem addressed by the Toronto team is twofold: firstly, that severe burns often cause damage to both the epidermis and the dermis (the outer and inner skin layers, respectively), which contain different cells and cell structures and therefore require specialized treatments. In such cases, Leng tells CBC news, “It’s very difficult for the body to regenerate itself.” Being able to close these wounds quickly, she added, is paramount to preventing fatalities. The second issue the team tackled was the need to produce flexible, skin-like materials with 3D printers which would survive grafting procedures; conventional 3D printers, they found, work best with harder materials, and have been unable to structure usable skin grafts involving complex layering of different cells needing different environments.
With the help of Boyang Zhang, a recent PhD, Axel Guenther, an associate professor of mechanical and industrial engineering at the University of Toronto, and burn surgeon Dr. Marc Jeschke, the students worked to develop a new kind of printer cartridge. Their special cartridge contains “tiny channels filled with skin cells and the liquid environment they require.” Prior to printing, the epidermal and dermal cells, “along with their specialized liquid, are kept in two different channels,” the CBC explained. During printing, each layer of artificial skin is dispensed as a liquid into yet another liquid, which causes it to solidify into a gel. The two solidified layers are then printed together, one on top of the other, to generate a biodegradable dressing containing the skin cells needed to treat deep skin wounds.
To date, the team’s 3D-printed grafts of human skin have helped immune-compromised mice with wound healing. The team hopes to work with larger grafts in pigs soon, and to begin human clinical trials within two to three years. This summer, the US Army reported that its researchers would soon begin clinical trials to test its own skin-printing technology. It remains to be seen, however, whether or not this Canadian team will beat them to the punch.
University of Toronto