In a landmark study, researchers from Northwestern University and the Washington University School of Medicine describe a novel biodegradable implant designed to electrically stimulate damaged nerves, speeding up the healing process, before naturally dissolving into the body.

In a case of peripheral nerve injury we know that nerves can regenerate, but that can often be a slow and inefficient process, sometimes leaving a numbness or tingling in hands, arms or legs. We also know that administering electrical stimulation to the damaged nerves can boost healing, but outside of surgery there's currently no way to continuously deliver that helpful electrical boost.

The remarkable new device is designed to wrap around a damaged nerve and deliver programmed bursts of electrical stimulation. The current prototype is about the size of a dime, and able to operate wirelessly for up to two weeks before naturally dissolving into the body.

Early tests in rats showed that the device does indeed speed up nerve signaling and muscle mass recovery, and was also found to effectively reabsorb into the body with no adverse effects noted. As this is the first time researchers have been able to study the effect of continuous electrical nerve stimulation on recovery, the next stage of the research is to better understand the optimal duration of stimulation.

"Before we did this study, we weren't sure that longer stimulation would make a difference, and now that we know it does, we can start trying to find the ideal time frame to maximize recovery," says Wilson "Zack" Ray, co-senior author on the study. "Had we delivered electrical stimulation for 12 days instead of six, would there have been more therapeutic benefit?"

The device described in the study is designed to function for two weeks before dissolving into the body. However, the researchers suggest this timeframe can be easily modified by varying the materials in the device, so future iterations could function for anything between a few days up to many weeks. The absorbable nature of the electrical stimulation device, which eliminates the need for secondary, and dangerous, implant removal surgeries, opens up a significant array of broad uses beyond just peripheral nerve stimulation.

"This notion of transient electronic devices has been a topic of deep interest in my group for nearly 10 years – a grand quest in materials science, in a sense," says John Rogers, co-senior author on the research. "We are excited because we now have the pieces – the materials, the devices, the fabrication approaches, the system-level engineering concepts – to exploit these concepts in ways that could have relevance to grand challenges in human health."

At this stage the device has not been tested in humans, so much work is still needed before it could appear in broad clinical uses, but the concept of a temporary, biodegradable implant that can naturally dissolve into the body after doing its job is undoubtedly exciting. As well as offering a novel approach to treating peripheral nerve damage, it is suggested the technology could be adapted to become a temporary pacemaker or an electrical interface with the spinal cord.

"This approach to therapy allows one to think about options that go beyond drugs and chemistry," says Rogers.

The new study was published in the journal Nature Medicine.

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