This may be technology at its coolest. Or grossest. Or both. We’d say both. Scientists in Madrid have figured out a way to produce functional sheets of human skin using a 3D printer. They published their results in the journal Biofabrication.

Scientists have really seized 3D printing as a solution to all kinds of problems. In the last few years, they’ve developed techniques for printing cardiac stents, artificial rat models to spare real rats from dissection—even human jawbones and ears. Other researchers have been hard at work growing human skin in the laboratory.

The team in Madrid decided to put the two concepts together. As you can imagine, this was not a simple matter of loading up the ink and hitting a button. The team built a brand-new type of bioprinter that uses human plasma as a medium, or scaffolding.

Co-author Juan Francisco del Cañizo is a surgeon at Madrid’s Hospital General Universitario Gregorio Marañón. He said it was tricky to create an automated process that could create a friendly environment for skin to grow. “Knowing how to mix the biological components, in what conditions to work with them so that the cells don’t deteriorate, and how to correctly deposit the product is critical to the system,” he told The Independent.

The printed skin includes the same functional layers as the home-grown variety: a tough, epidermis-like outer layer; a thick middle layer; and a layer of collagen-producing cells to make the skin stretchy and strong.

The research team believes their new skin printer has huge potential for helping burn patients and other people who need skin grafts. The printer could include the patients' own cells in the plasma medium, which would significantly decrease the odds that their bodies would reject the new skin.

Animal advocates see the skin as a chance to put an end to cosmetic companies’ animal testing, which currently relies on rabbits, guinea pigs, mice, and dogs as surrogates for human skin.

A bioengineering firm called the BioDan Group has already expressed an interest in mass-producing the skin printers.