Magnetic workout mat helps muscle cells grow and work together

The researchers created a magnet-containing gel mat that simulates the mechanical forces exerted on muscle cells during exercise. The new training mat could help test treatments for people with muscle injuries and neuromuscular diseases or develop artificial muscles for use in soft robots.

In the body, cells communicate through a combination of chemical, electrical and mechanical signals, especially during exercise. With lab-made cells, creating mechanical contact between cells can be difficult because it can often cause damage to the cells.

MIT researchers have created a non-harmful way to simulate the mechanical effects that skeletal muscle cells are exposed to during exercise. They want you to think of it as a training mat for cells.

Here, we wanted to dissociate the two main elements of chemical and mechanical exercise to see how muscles respond purely to the mechanical forces of exercise, said Ritu Raman, corresponding author of the study.

Researchers have turned to magnets as a way to expose muscle cells to regular, repeated mechanical forces without causing damage. By mixing commercially available magnetic nanoparticles with a rubbery silicone solution, the mixture was cured to form a plate and cut into very thin bars. A prototype mat was created, consisting of four slightly spaced magnetic bars sandwiched between two layers of hydrogel.

Muscle cells were placed on the surface of the tapetum, and the circular cells gradually elongated and fused with neighboring cells to form fibers. Below the gel mat, the researchers placed an external magnet on a track and programmed it to move back and forth. Magnets embedded in the gel moved in response, shaking the gel and generating forces similar to what cells would experience during exercise in the real world. They exercised the cells for 30 minutes a day for 10 days. A group of non-exercised muscle cells acted as a control.

So we zoomed out and took a picture of the gel and found that these mechanically stimulated cells looked very different from the control cells, Raman said.

They found that the exercised cells grew larger and turned into fibers that aligned in the same direction. In contrast, control cells tended to remain circular and were randomly aligned.

Under normal circumstances, muscle cells would contract in response to an electrical nerve impulse, but under laboratory conditions this could damage the cells. So researchers genetically modified cells to contract in response to blue light.

When we shine a light on the muscles, we can see that the control cells are beating, but some fibers are beating this way, others that way, and generally producing very asynchronous contractions, Raman said. With the fibers aligned, they all pull and beat at the same time, in the same direction.

Researchers say the new workout gel could be used as a quick, non-invasive way to shape muscle fibers and study how they respond to exercise, which could identify therapies to help people recover from muscle injuries and neuromuscular disorders. . They also plan to grow other cell types in the gel to research how they respond to “exercise.”

There is evidence from biology to suggest that many cell types respond to mechanical stimulation, Raman said. And this is a new tool for studying interaction.

The study was published in the journal Device.

Source: MIT