Biological bandages from a 3D printer, for use in space

February 17, 2022

(News from Nanowerk) When it comes to burns or abrasions that measure several square centimeters in total area, the self-healing powers of the body are overwhelmed and often only an autologous skin graft can help. But problems arise both during skin removal and transplantation, says Professor Georg Duda, director of the Julius Wolff Institute for Biomechanics and Musculoskeletal Regeneration at BIH and spokesperson for the BIH Center for Regenerative Therapies (BCRT). “Unfortunately, skin grafts often result in scarring, which is not a satisfactory outcome, both medically and cosmetically, for neither the doctor nor the patient.”

In their search for an alternative, Duda’s team of scientists came across Cellbricks, a company that has developed a 3D printer capable of producing custom skin patches in different sizes and shapes.

A 3D printer capable of producing biological wound closure in a box that withstands the stresses of parabolic flight. (Photo: Bianca Lemke / BIH)

Biological printing ink

“In our case, the printing ink is biological,” says Bianca Lemke, a PhD student working with Professor Duda. “It consists of a special form of gelatin with methacrylate ends that hardens when exposed to UV light. We mix this with skin cells that ideally come from the transplant recipient. And if we go very far technically, we can even print tiny tubes in the mixture, which we then fill with blood vessel cells to make sure the skin patch contains blood vessels.

The shape and size of the wound closure required can be adjusted on the printer, and printing can take one or more hours depending on the difficulty of the particular bandage.

“At a symposium organized by the German Aerospace Center (DLR), the question arose whether 3D bioprinting could not also be used for astronauts,” says the engineering graduate. “After all, it’s a long way to Mars, and even from the ISS you can’t get back to Earth quickly if you’ve suffered a serious injury. And that’s where a custom solution like this would be quite handy.

But now the question arises whether such a 3D printer would work even in weightlessness or weightlessness. Won’t liquid ink float? Will the gelatin harden as expected?

Parabolic flight experience

In order to answer these questions, Lemke takes off today from Paderborn for a parabolic flight on which the 3D printer will be tested. “Various security checks will be carried out before take-off. Since we print with liquids and these could spread throughout the plane during microgravity phases, we must of course take measures to avoid this. The printers are located in a box that must withstand various tests and mechanical stresses, so this will also be checked. After that, everything will be covered in padding, so that none of the participants accidentally hit their head while floating around the cabin of the plane. And then everything goes on the plane where it will be mounted. Various functional tests are carried out on board the aircraft to ensure that everything works here too. And then we take off!”

During the five-hour flight, 31 parabolas are flown, meaning the aircraft flies upward in a parabolic arc, then descends steeply before flying upward again. During the upper part of the parabola, weightlessness is felt for about 20 seconds; during ascent and descent, several gravitational forces are produced for a short time.

To check how the gravitational force of the Earth affects the printing result, Lemke will embed microbeads in the printing ink: “These microbeads are small fluorescent spheres the size of a cell. We use them to study the sedimentation behavior of cells during flight. Indeed, we have already observed on Earth that cells sink when the ink remains stationary longer. We fear that all cells will sink during hypergravity phases, but we hope that in weightlessness no cell will sink at all.

Professor Duda will remain on the ground and is eager to hear the results: “We really hope that the printing results will be stable at least in weightlessness, because it would mean that we could indeed one day offer astronauts personalized wound care. Although there is still a long way to go until then. »