Scientists say they have developed the first bioelectronic medicine -- an implantable, biodegradable wireless device that speeds nerve regeneration and improves the healing of a damaged nerve.
Researchers at the Washington University in the US developed a device that delivers regular pulses of electricity to damaged peripheral nerves in rats after a surgical repair process, accelerating the regrowth of nerves in their legs and enhancing the ultimate recovery of muscle strength and control.
The size of a dime and the thickness of a sheet of paper, the wireless device operates for about two weeks before naturally absorbing into the body, according to the study published in the journal Nature Medicine.
The researchers envision that such transient engineered technologies one day could complement or replace pharmaceutical treatments for a variety of medical conditions in humans.
The technology, called "bioelectronic medicine," provides therapy and treatment over a clinically relevant period of time and directly at the site where it's needed, thereby reducing side effects or risks associated with conventional, permanent implants.
"These engineered systems provide active, therapeutic function in a programmable, dosed format and then naturally disappear into the body, without a trace," said John A Rogers from the Northwestern University in the US.
"This approach to therapy allows one to think about options that go beyond drugs and chemistry," Rogers said.
While the device has not been tested in humans, the findings offer promise as a future therapeutic option for nerve injury patients, researchers said.
For cases requiring surgery, standard practice is to administer some electrical stimulation during the surgery to aid recovery.
However, until now, doctors have lacked a means to continuously provide that added boost at various time points throughout the recovery and healing process.
"We know that electrical stimulation during surgery helps, but once the surgery is over, the window for intervening is closed," said Wilson Ray, an associate professor at Washington University.
"With this device, we have shown that electrical stimulation given on a scheduled basis can further enhance nerve recovery," Ray said.
Over the past eight years, Rogers and his lab developed a complete collection of electronic materials, device designs and manufacturing techniques for biodegradable devices with a broad range of options that offer the potential to address unmet medical needs.
The researchers designed and developed a thin, flexible device that wraps around an injured nerve and delivers electrical pulses at selected time points for days before the device harmlessly degrades in the body.
The device is powered and controlled wirelessly by a transmitter outside the body that acts much like a cellphone-charging mat.
Researchers then studied the bioelectronic device in rats with injured sciatic nerves which send signals up and down the legs and control the hamstrings and muscles of the lower legs and feet.
They used the device to provide one hour per day of electrical stimulation to the rats for one, three or six days or no electrical stimulation at all, and then monitored their recovery for the next 10 weeks.
The researchers found that any electrical stimulation was better than none at all at helping the rats recover muscle mass and muscle strength.
The more days of electrical stimulation the rats received, the more quickly and thoroughly they recovered nerve signalling and muscle strength. No adverse biological effects from the device and its reabsorption were found.
By varying the composition and thickness of the materials in the device, Rogers and colleagues can control the precise number of days it remains functional before being absorbed into the body. New versions can provide electrical pulses for weeks before degrading.
The ability of the device to degrade in the body takes the place of a second surgery to remove a non-biodegradable device, thereby eliminating additional risk to the patient.