Scientists develop implant that relieves pain without drugs

A team of researchers led by Northwestern University has developed a dissolvable implant that quickly relieves pain 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 and control its intensity at the onset of pain. The implant would not need to be surgically removed as it is water soluble and will easily dissolve.

“The technology described here exploits mechanisms that share some similarities to those that cause your fingers to feel numb when it’s cold. Our implant makes it possible to produce this effect directly and locally on targeted nerves, even those deep in the surrounding soft tissues, in a programmable way,” said Rogers.

The implant is 5 millimeters long at its widest point. It works by gently wrapping itself around a single nerve while another end attaches to the control pump outside the skin. The implant vaporizes a liquid coolant in the target area, which numbs the nerve and blocks pain signals to the brain.

Evaporation occurs via tiny microfluidic channels in the implant, one channel containing the coolant perfluoropentane – a clinically approved ultrasound contrast agent also used for pressurized inhalers, and another channel containing dry nitrogen, an inert gas. When the coolant and gas flow into the same chamber, evaporation occurs immediately, and an onboard sensor monitors the nerve to ensure its temperature does not drop to levels that could cause tissue damage.

“Excessive cooling can damage the nerve and the fragile tissues around it,” Rogers said. “Duration and temperature of the cooling must therefore be precisely controlled. “By monitoring the temperature at the nerve, flow rates can be automatically adjusted to establish a point that blocks pain in a reversible and safe manner.”

“When you cool a nerve, the signals traveling through the nerve slow down and eventually stop completely,” said study co-author Dr. Matthew MacEwan of Washington University School of Medicine in St. Louis.

“We’re specifically targeting the peripheral nerves that connect your brain and spinal cord to the rest of your body. These are the nerves that transmit sensory stimuli, including pain. MacEwan said, “By applying a cooling effect to just one or two targeted nerves, we can effectively modulate pain signals in a specific region of the body.”

Researchers believe their device will be a safe alternative to opioids and other highly addictive drugs. They see the greatest benefits for people undergoing routine surgeries and for amputees who need post-surgery pain relief medication.

“While opioids are extremely potent, they are also extremely addictive,” Northwestern’s John A. Rogers, who led the development of the device, told Reuters. “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, having previously tested it on rats. He says more needs to be learned about the human body to make the device more compatible and prevent potential side effects like hypothermia.

“After you stop cooling, how long does it take for the nerve to recover so you can start cooling again?” he says. “These are the types of studies that I think are most important before a device is used with humans.”

With mail wires