A Russian cosmonaut aboard the ISS has 3D printed human tissue for the first time in the microgravity of space. The cosmonaut used a magnetic levitation device created by Russian researchers to fabricate human cartilage from a few isolated cells. The scientists say that the work could lead to new techniques for regenerating tissues during long-term spaceflight.
Traditional tissue engineering involves seeding cells onto biocompatible “scaffolds,” which biodegrade once the tissues have assembled themselves into 3D organs. There are newer and more flexible approaches that don’t require the scaffold emerging. These techniques allow cells to assemble themselves without the need for a structural biomaterial.
Researchers have invented these techniques using things like removable supports and guiding forces from acoustic electrostatic fields. One of the promising approaches for scaffold-free construction of human tissue uses magnetic levitation. With that technique, strong field gradients can precisely guide tissue cells in the place.
The technique does require cells to be suspended within a paramagnetic medium containing gadolinium ions. One challenge is that at concentrations necessary for the method to work, the ions are toxic to cells and can cause dangerous imbalances in pressure. One of the potential methods of getting around those problems is to perform levitated assemblies and microgravity, which led to the experiment aboard the ISS.
The researchers first fabricated tissue spheroids from human cartilage cells at the Baikonur Cosmodrome in Kazakhstan. Those spheroids were then embedded in a heat-reversible hydrogel and delivered to the ISS inside hermetically sealed cuvettes. Once the cells were extracted aboard the ISS, the self-assembly process was captured by cameras and showed a strong agreement with the mathematical models and computer simulations. The experiment was a success and represents an advance in the ability to fabricate 3D human tissues without scaffolds and non-toxic levels of gadolinium ions.