Scientists grow cells on a robot skeleton (but don’t know what to do with them yet)

The science of tissue engineering — or culturing human cells for use in medicine — is still in its infancy, with only the simplest lab-grown cells able to be used in experimental treatments today. But researchers say a new method of tissue engineering could potentially improve the quality of this work: growing the cells on a moving robot skeleton.

Usually, cells used in this type of regenerative medicine are grown in static environments. Think of: petri dishes and miniature 3D scaffolds. A few experiments in the past have shown that cells can be grown on moving structures such as hinges, but these have stretched or bent the tissue in only one direction. But researchers from the University of Oxford and robotics company Devanthro thought that if you want to grow matter designed to move and bend like tendons or muscles, it would be better to mimic their natural growth environment as closely as possible. So they decided to approach a mobile human body.

Growing cells in a real person naturally poses all kinds of problems, so the multidisciplinary team decided to get the best possible approach to the human musculoskeletal system using a robot. As described in a paper published in communication technology, they adapted an open-source robotic skeleton designed by the engineers at Devanthro, and created a custom growth environment for the cells that can be placed within the skeleton to bend and bend as needed. (Such culture environments are known as bioreactors.)

The place they chose for this tissue farming was the robot’s shoulder joint, which had to be upgraded to more closely approximate our own movements. They then created a bioreactor that could be fitted into the robot’s shoulder, made up of strands of biodegradable filaments stretched between two anchor points, like a strand of hair, with the entire structure enclosed by a balloon-like outer membrane.

The skeleton is adapted from the open-source Roboy model.
Image: Fisher Studios

The hair-like filaments were then seeded with human cells and the chamber flooded with a nutrient-rich fluid designed to stimulate growth. The cells were cultured over a two-week period during which they enjoyed a daily exercise routine. Every day for 30 minutes, the bioreactor was shoved in the shoulder and, for lack of a better term, tossed (albeit in a very scientific way).

Here’s the big caveat, though: While the team observed changes in the exercise cells that were different from those grown in a static environment, they’re not sure yet if those changes were any good.

The project’s lead researcher, Pierre-Alexis Mouthuy of the Botnar Institute of Musculoskeletal Sciences at the University of Oxford, told The edge that the differences he and his colleagues observed in the cells cultured in this way — which were based on measuring the activity and growth of certain genes — were ambiguous at best in terms of future medical applications.

“We do get differences from the charging regime [the movement of the bioreactor in the robot shoulder joint] but do those differences also mean better cells? We don’t know that yet’, says Mouthuy. “We are not saying that this system is better than the others. Or there is one movement that is better than the other. We only show the feasibility.”

So: the team has shown that culturing cells in a robot skeleton is certainly possible. Now they just need to figure out if it’s worth the time. In the paper, however, the researchers enjoyed some optimistic speculation about the potential of this work. They reason that in the future, detailed scans of patients could be used to make joint-perfect replications of their bodies, allowing tissue-like tendons to be cultured for surgery in a human simulation.

For now, though, it’s back to the drawing board — or rather, the robotic skeleton. As Mouthuy says, “We need to do a lot more work to understand what’s really going on.”


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