A team of researchers led by Northwestern University has developed a dissolvable implant that provides rapid pain relief without the use of drugs, according to a study published in Science.
The biocompatible implant is controlled by an external pump that allows the patient to activate it as soon as pain appears and to control its intensity. The implant would not require surgery to remove as it is water soluble and simply dissolves.
“The technology reported here exploits mechanisms that bear some similarities to those that cause your fingers to go numb when cold. Our implant allows this effect to be produced programmatically, directly and locally on targeted nerves, even those deep within the surrounding soft tissue,” Rogers said.
The implant is 5 millimeters long at its widest point. It works by gently wrapping around a single nerve, while another end is attached to the control pump outside the skin. The implant evaporates a coolant in the targeted area, which numbs the nerve and blocks pain signals to the brain.
Evaporation is achieved through tiny microfluidic channels contained within the implant, one channel contains the refrigerant perfluoropentane – a clinically approved ultrasonic contrast agent which is also used for pressurized inhalers, and another channel contains dry nitrogen , an inert gas. When coolant and gas flow in the same chamber, evaporation occurs instantaneously, and a built-in sensor monitors the nerve to ensure that its temperature does not drop to a level that might damage tissue.
“Excessive cooling can damage the nerve and the fragile tissues around it,” Rogers said. “The cooling time and temperature must therefore be precisely controlled. “By monitoring temperature at the nerve, flows can be automatically adjusted to set a point that reversibly and safely blocks pain.”
“As you cool a nerve, the signals traveling through the nerve become slower and slower – eventually stopping altogether,” said study co-author Dr. University of Washington in St. Louis.
“We specifically target the peripheral nerves, which connect your brain and spinal cord to the rest of your body. These are the nerves that communicate sensory stimuli, including pain. Dr MacEwan said: “By producing a cooling effect on just one or two targeted nerves, we can effectively modulate pain signals in a specific region of the body.”
The researchers believe their device will be a safe alternative to opioids and other highly addictive drugs. They predict its greatest benefits will go to people undergoing routine surgeries and amputees who need post-operative medication to manage pain.
“While opioids are extremely effective, they are also extremely addictive,” Northwestern’s John A. Rogers, who led the device’s development, told Archyde.com. “As engineers, we are driven by the idea of treating pain without drugs.”
Rogers tells the Smithsonian that more studies are needed before the implant can be tested in humans, it has already been tested in rats. He says more needs to be learned regarding the human body to make the device more compatible and prevent possible side effects like overcooling.
“After stopping cooling, how long does it take for the nerve to recover so you can restart cooling?” he says. “These are the types of studies that I think are the most important to conduct before using a device with humans.”
With pole wires
