The International Space Station is an incredible laboratory that allows us to study the world in a way we can’t reproduce on Earth. The latest example of this is the first construction of engineered cartilage without scaffold tissue. Instead, it was built using magnetic levitation bioassembly.
Tissue engineering is a cutting-edge field that may sound like sci-fi but is very real. Still, some obstacles have proven difficult to overcome. One such example is the scaffolding to build the tissue itself. You can think of scaffolding as the mold of whatever pieces of flesh or organ you are creating. To use this tissue, the mold must be able to come off.
For this reason, scientists have been investigating approaches that do not require a structure to help with the assembly. Microgravity can help with that, and tissues have been built in space before, but it's important to have a tool that can push material together. That’s where the magnets come in.
Cells are not naturally magnetic so compounds known as gadolinium chelates are commonly used. Unfortunately, these are toxic to cells with doses normally used on Earth. Another reason why going to space with the method is attractive.
The team used a thermoreversible hydrogel into which they dropped little spheres of cartilage that were imbued with a low dose of gadolinium chelates. Cosmonaut Oleg Kononenko placed these samples in a specially designed magnetic bioassembler. There the little spherules of cartilage were able to merge into a tissue.
A blob of cartilage is not a fully functional 3D-printed organ, but it is an exciting first step in this technique in space. The innovative approach has many potential applications, both in the construction of organic and inorganic materials (even both at the same time). This could be used in technological applications beyond the realm of medicine.
The next step for the researchers is to construct something more complex. They will combine magnetic fields with sound waves to build something cylindrical, similar to a trachea or urethra, but for now on a smaller scale.