Implantable device for pain-free pain relief

Researchers at Northwestern University have developed a small, soft and flexible implantable device that can provide pain relief on demand without the need for drugs and solvents. According to the team, the device has a high value for patients undergoing routine surgery or having a limb that requires medication after surgery. Surgeons may implant the device during the procedure to ease the patient's post-operative pain. The study, published July 1 in the journal Science, describes the device's design and performance in animal models.

The flexible implant is easy to stretch and bend inside the body.

"Although opioids are extremely effective, they are also addictive," said study leader John A. Rogers of Northwestern University. "As engineers, we were driven by the idea of ​​treating pain without medication in a way that can be activated or stopped immediately. In animal models, our implant demonstrates This effect can be pre-programmed, targeting local nerves even those around soft tissue."

The implant is based on a simple concept of evaporation. It contains a liquid coolant that evaporates at a specific location of the sensory nerve. The device works by wrapping around the nerve, providing precise and targeted cooling. This paralyzes the nerve and blocks pain signals from reaching the brain. An external pump allows the user to remotely activate the unit and control its intensity. When the device is no longer needed, it is naturally absorbed into the body, eliminating the need for surgery to remove. At the thickness of a sheet of paper, the nerve-cooling elastomer device is ideal for treating highly sensitive nerves.

Dr. Matthew MacEwan of Washington University School of Medicine in St. Louis says that as nerves get cooler, the signals traveling through them become slower and eventually stop altogether. "We targeted the peripheral nerves, which connect the brain and spine to the rest of the body. These are the nerves that convey sensory stimuli, including pain. By providing an effective delivery. cooling one or two nerves, we can effectively modulate pain signals in a specific area of ​​the body," explains MacEwan.

The device contains tiny microfluidic channels that transmit the cooling effect. While one channel contains perfluoropentane liquid coolant, the other contains dry nitrogen. When the liquid and gas flow into the shared chamber, a reaction occurs that causes the liquid to immediately evaporate. The microscopic built-in sensor monitors the temperature of the nerve to prevent extreme cold, which can cause tissue damage.