Printed skin for burn victims

In this year’s James Dyson Award competition, there were over 600 entries from 18 different countries. Participants vying for the international design award were asked to design a device that solves a problem. Although many innovative designs were submitted, the winning designs were few and far between. One of the lucky winning designs included a 3D skin tissue printer developed by University of Toronto engineering students Arianna McAllister and Lian Leng.

18_3d printing_Subhashish PanigrahiThe PrintAlive Bioprinter is a major step towards increasing the survival and recovery rates of burn victims. The printer is able to produce imitations of the epidermal and dermal layers of human skin and could potentially be used to help close the wounds of severe burn victims in order to promote recovery. The 3D-printed grafts of human skin have proven to be successful in improving wound healing in immune-compromised mice. The next stage of testing involves larger grafts in pigs, which, if successful, McAllister and Leng hope will lead to human clinical trials commencing in two to three years’ time.
The impressive design is able to print the complex multicellular structures that make up the skin; a special cartridge had to be designed, as the different skin cells require different environments. The cartridge consists of small channels filled with skin cells and the specific hydrogel environment they require. The different cell types include keratinocytes, the most common cells in the epidermis, and fibroblasts, which are important in maintaining the structural integrity of connective tissues. Both cell types are used for the two different layers, along with their specialized hydrogel; these are kept in two different channels. Each layer is released in liquid form, which combines with another liquid that causes it to solidify into a gel as it leaves the printer. The two layers are then printed together, one on top of the other, in the specific order needed to create the desired patterns.

The PrintAlive Bioprinter is revolutionary with regards to current burn treatments available. The printer will print new skin for burn victims far faster than existing methods which is important as patient survival is inversely proportional to the time required for wound stabilization and coverage. Culturing skin cells to grow enough to be ready for grafting can take up to 14 days, which is slow in comparison to the 3D skin tissue-printing device. There are a range of limitations with existing skin grafting technologies; substantial tissue donations from the patient themselves are required and therefore limits the applicability in cases of severe burns where significant tissue donations are not possible.

The 3D printer, however, does not have any limitations with regards to how much skin it is able to print. It also reduces financial cost due to its efficiency, as scientists are able to localize high concentrations of human cells rather than homogeneously populating the entire sheet, reducing the number of cells required by up to 75%. Furthermore, allografts can increase the chance of infection through transmission of pathogens from donor to recipient and may also cause patients to reject the graft, resulting in scarring and complications. Skin grafting procedures require the removal of skin from a donor site somewhere else on the body, which can prove to be a painful process for the patient, since it forces their body to heal a secondary injury on top of the first. The PrintAlive Bioprinter, however, does not carry such risk, as it is able to work independently of grafts, meaning that future burn victims will not experience any more pain or scarring as the skin will not be grafted from a donor site somewhere else on the body.

For winning the Canadian stage of the award, the team at University of Toronto will receive $3,500 to help further develop the technology. This 3D skin tissue printer could prove to be the future for burns’ treatments.

Photo credit: Subhashish Panigrahi

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