Researchers have created “skin in a syringe,” a gel containing live cells that can be 3D printed into a skin transplant, according to new research in mice.

“The dermis is so complicated that we can’t grow it in a lab. We don’t even know what all its components are. That’s why we, and many others, think that we could possibly transplant the building blocks and then let the body make the dermis itself,” says Johan Junker, a researcher at the Swedish Center for Disaster Medicine and Traumatology and docent in plastic surgery at Linköping University, who led the study published in Advanced Healthcare Materials.

The fibroblast is easy to remove from the body and grow in a lab. The connective tissue cell also has the advantage of being able to develop into more specialized cell types depending on what is needed. The researchers provided a scaffold by having the cells grow on tiny, porous beads of gelatine, a substance similar to skin collagen. But a liquid containing these beads poured on a wound will not stay there.

The New Solution

The researchers’ solution is mixing the gelatine beads with a gel consisting of hyaluronic acid. When the beads and gel are mixed, they are connected using what is known as click chemistry. The result is a gel that, somewhat simplified, can be called skin in a syringe.

“The gel has a special feature that means that it becomes liquid when exposed to light pressure. You can use a syringe to apply it to a wound, for example, and once applied it becomes gel-like again. This also makes it possible to 3D print the gel with the cells in it,” says Daniel Aili, Professor of Molecular Physics at Linköping University, who also led the study.

In the current study, the researchers 3D-printed small pucks that were placed under the skin of mice. The results point to the potential of this technology to be used to grow the patient’s own cells from a minimal skin biopsy, which are then 3D-printed into a graft and applied to the wound.

“We see that the cells survive, and it’s clear that they produce different substances that are needed to create new dermis. In addition, blood vessels are formed in the grafts, which is important for the tissue to survive in the body. We find this material very promising,” says Junker.