The implantable device that blocks pain by cooling the nerves –

From Christina Maroney

The device, made of biodegradable materials, cools the nerves up to 10 degrees. So far it has been successfully tested on mice with the aim of not taking drugs. Research published in the journal Science

A team of researchers led by Northwestern University has developed a small, soft and flexible implant Pain relief (upon request) without the need to take drugs. The first device of its kind, built with biodegradable materials absorbed by the body over time, can provideto me

TheAn important alternative to opiates
And other drugs that can cause addiction. The prototype has so far been successfully tested in mice and the study is published in the July 1 issue of Science.

Remote activation and without drugs

The device works by gently twisting the nerves: it causes a Precise and targeted cooling
up to 10 degreeswhich – which It numbs the nerves and blocks pain signals from the brain. An external pump that allows the patient to do so Activate the device remotely, Increase or decrease the intensity according to the need of the moment. When the device is not needed, the body absorbs it without having to resort to surgery to extract it. The researchers noted that the device could be extremely useful for patients undergoing routine surgery or even amputations that require large doses of post-operative medication to control pain. Rogers John A. “As engineers, we are motivated by the idea of ​​treating pain without drugs, with devices that can be turned on and off instantly, with the user in direct control of the intensity of comfort. Our implant reproduces the effect we feel when the hands, due to extreme cold, become numb but are applied in a targeted manner. on nerves, even those in the depths of soft tissues».

tests on mice

To test its functionality, the device was an iImplanted around the sciatic nerve Three legs of mice. Then there were injuries to the legs, so that they became more sensitive. After three weeks, each time a painful mouse’s paw was pressed with a particular device, the force required seven times for the animals to retract its paw when the device was on, a sign thatThe party was drugged. Six months later, the body has reabsorbed the device No nerve damage was observed. says Rogers, a bioelectronics pioneer, professor of materials science and engineering, biomedical engineering and neurosurgery in the McCormick School of Engineering and Northwestern University Feinberg School of Medicine.

How it works

While the new device may sound like science fiction, it benefits from a simple and common concept that everyone knows:evaporation
. Just as the evaporation of sweat cools the body, the device contains a coolant that is stimulated to evaporate when placed on a nerve. To induce a cooling effect, the device contains microfluidic channels. One channel contains Refrigerant (perfluoropentane)It is clinically approved as a contrast agent for ultrasonic inhalers and pressurized inhalers. The second channel contains dry nitrogen, Stable gas. When a liquid and gas flow into a common chamber, one of them occurs A reaction that makes the liquid evaporate quickly. At the same time, a small, built-in sensor monitors the temperature of the nerve to make sure it doesn’t get too cold, which can lead to tissue damage. “Excessive cooling can damage the nerve and the fragile tissues around it,” Rogers explains. “Therefore, the duration and temperature of refrigeration must be carefully controlled. Work in progress attempts to define the full range of time and temperature thresholds below which the process remains fully reversible.”

Other Attempts

Many of the previous pain relief methods that worked in mice did not work in humans, and it is well known that cooling nerves impairs their function. Previously, researchers also discovered injection cryotherapy. But rather than targeting specific nerves, these imprecise methods approach large areas of tissue, which can lead to unwanted effects such as tissue damage and inflammation. Even electrical stimulation to silence painful stimuli has limitations because activation of the device causes pain and muscle contractions, which is not ideal from the patient’s point of view.


Instead, the new device has the advantage of being very small, measuring just 5 millimeters wide at its widest point. By precisely targeting only the affected nerve, the device does not involve the surrounding areas due to unnecessary cooling, which can cause side effects. “We don’t want to inadvertently cool nerves or tissues that have nothing to do with the nerve that transmits painful stimuli to the brain – he confirms Matthew McEwan, of Washington University School of Medicine in St. Louis and co-author of the study. “We want to block pain signals, not the nerves that control motor function and allow, for example, hand use.”

Jul 1, 2022 (change on Jul 1, 2022 | 16:37)

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