Fight pain without drugs
A small, soft and flexible implant has now been developed which is capable of providing pain relief when needed without the use of medication. After use, the device is easily absorbed by the body.
A new study involving researchers at Northwestern University has presented an implantable, bioresorbable, microfluidic device that enables targeted, minimally invasive cooling to any depth in living tissue with real-time temperature monitoring.
The results of the study have been published in the English-language journal Science.
The cold numbs the nerves
The biocompatible, water-soluble device is only five millimeters wide at its widest point. It gently wraps around nerves and provides precise, targeted cooling that numbs nerves and blocks pain signals to the brain, the researchers explain.
No side effects
Since the device is very precise and only touches the desired nerve, the surrounding regions are not cooled unnecessarily, which avoids possible side effects, the research team continues. It is also possible to increase or decrease the intensity with an external pump.
The device is absorbed by the body
The components of the new device are biocompatible. In other words, once it is no longer needed, it is naturally absorbed into the body’s biofluids over days or weeks, eliminating the need for surgical removal.
Relieve pain after surgery
The device could be particularly beneficial for people undergoing routine surgeries or even amputations, which often require postoperative medication.
The team explains that cooling could already be surgically implanted during the procedure in order to relieve patients’ postoperative pain.
“As engineers, we are driven by the idea of treating pain without drugs, in a way that can be turned on and off instantly, with the user controlling the intensity of relief,” said the author of study, John A. Rogers. in a press release.
The new technology uses mechanisms similar to those that cause fingers to go numb in cold weather. The implant makes it possible to generate this effect directly and locally on the target nerves, even those located deep in the surrounding soft tissues, in a programmable manner.
How are the nerves cooled?
The device is based on the concept of evaporation. Similar to how evaporating sweat cools the body, the device contains a coolant that is sprayed at a specific location on a sensory nerve, the expert adds.
For the cooling effect to occur, the device contains so-called tiny microfluidic channels in which a coolant (perfluoropentane) is present. A second channel contains dry nitrogen.
When liquid and gas flow through a common chamber, a reaction occurs, immediately evaporating the liquid and creating a cooling effect, the researchers explain.
“When you cool a nerve, the signals going through the nerve slow down and eventually stop,” adds study author Dr. Matthew MacEwan of Washington University School of Medicine in St. Louis.
Which nerves are targeted?
“We specifically target the peripheral nerves that connect the brain and spinal cord to the rest of the body. These are the nerves that transmit sensory stimuli, including pain.
By targeting just one or two nerves, pain signals can be effectively modulated in a specific region of the body, explains Dr. MacEwan.
Sensor prevents tissue damage caused by hypothermia
A small built-in sensor monitors the temperature of the nerve. Care can be taken to ensure that the nerve does not become too cold, as this could damage tissue.
“Cooling too much can damage the nerve and the delicate tissues around it. The duration and temperature of the cooling must therefore be precisely controlled,” says Rogers.
Flow (and therefore cooling) is automatically adjusted to reach a point that reversibly and safely blocks pain.
“You don’t want to inadvertently cool other nerves or tissues that aren’t related to the nerve that transmits pain stimuli. We want to block pain signals, not the nerves that control motor function and allow you to ‘using your hand, for example,’ says MacEwan.
Eliminate painful stimuli with electrical stimulation?
Nerve blockers have been researched in the past, which deactivate painful stimuli with electrical stimulation. However, problems arose.
“You can’t turn off a nerve with electrical stimulation without turning it on first. here a better alternative.(like)
Author and source information
This text corresponds to the specifications of the specialized medical literature, medical guidelines and current studies and has been verified by health professionals.
Jonathan T. Reeder, Zhaoqian Xie, Quansan Yang, Min-Ho Seo, Ying YanYujun Deng, et al. : Soft, bioresorbable coolers for reversible conduction block of peripheral nerves; in: Science (published 06/30/2022), ScienceNorthwestern University: Dissolve implantable device reliefs pain without drugs (published 06/30/2022), Northwestern University
This article contains general advice only and should not be used for self-diagnosis or treatment. It cannot substitute a visit to the doctor.