A group of engineering freshmen at Rice University have come up with a clever way to make needles and injections less painful without the use of drugs. And it uses the same approach as those instant ice packs designed to reduce swelling and reduce the pain from a sports injury.
The simple 3D-printed capsule features two sealed chambers, one filled with ammonium nitrate, and the other with water. When the capsule is twisted those ingredients mix producing a chemical reaction the drastically cools a metal cap that can then be applied to a patient's skin to completely numb it in as little as 60 seconds.
So instead of having to wait an hour for the numbing effects of a topical patch to kick in, this allows a shot to be quickly administered.
The science behind the device is obviously well known — after all, it's widely used in ice packs and other applications where instant cooling is necessary. But what makes these students' invention unique is that eventually the capsule can be integrated into the caps of the sterile disposable needles used in hospitals around the world. So as a nurse is prepping an injection, a patient can use the cap to numb their skin and make the whole process of getting a shot far less painful and intimidating.