How Liquid Metal Can Be Used to Fix Nerve Damage

Over the last decade or so, most regenerative medicine research has focused on using stem cells to regenerate nerves (or create new ones) in an attempt to help paralyzed people regain function by repairing whatever connection was severed. But, maybe, there’s another way: For the first time ever, Chinese researchers have used liquid metal to reconnect a severed nerve and have been able to send electric pulses through it.

Granted, the experiment took place in dead bullfrogs, in a laboratory, but the technique points to some interesting possibilities for the future. In a preliminary paper published on arXiv, Jie Zhang of Tsinghua University suggests that a liquid metal alloy of gallium, indium, and tin can be used to patch nerves together, at least long enough for the nerves to either heal themselves or long enough for surgery to become an effective option to restore movement.

Nerve regeneration is an extremely slow process, with nerves growing at a rate of just a millimeter or two per day. During that time, a paralyzed patient is likely to suffer from muscle atrophy and other, sometimes irreversible side effects. If liquid metal could be used to form a temporary bridge to allow people to retain some muscle function, the thinking goes that those side effects will be lessened.

The alloy, dubbed GaInSn, offers a few advantages: For one, it conducts electricity well, which is crucial for the sending of messages back and forth through the nervous system. It also remains a liquid at room temperature (and all temperatures that humans are likely to encounter), so patients wouldn’t run the risk of having the material solidify on them throughout the course of a normal day. Zhang also suggests that if the nerve repairs itself sufficiently, the liquid metal could be easily removed from the body with a syringe. Finally, as far as we know, the alloy isn’t toxic, so it shouldn’t harm patients if it were used to help patch up nerves.

“The liquid metal GaInSn shows great virtues that no other conventional material possesses, and it is promising to achieve functional recovery during the regeneration of combining the nerve conduits with liquid metal,” Zhang wrote. The metal “might play an important role of the functional recovery channel cooperating with nerve conduits during regeneration.”

Of course, there’s no real timeline for when this could be possible in humans—what works on a frog’s leg in a laboratory might not work on someone’s spinal column. At the very least, it’s a promising development and it suggests that stem cells might not be the only way we’ll eventually be able to help nerves heal.