4 July 2022

Put pain in the fridge

Pain The Back Page

Like an internal icepack, this dissolvable implant takes the heat out of injuries.


We know that opioids after surgery are bad news and alternatives are needed.

So a big Back Page thumbs-up to the team from Northwestern University in Illinois that has developed a flexible, dissolvable tape to wrap around nerves post-procedure and deliver targeted cooling.

It’s basically a tiny Esky for post-operative pain. And really, since the Esky is an Australian invention, it’s a bit disappointing someone else got there first.

Image: Northwestern University

This tape contains microfluidic channels full of a bioinert coolant, and a thermal sensor that allows temperature to be monitored in real time. The user can turn the activity up or down remotely using an external pump.

At only 5mm wide at its widest point, the tape can be placed very precisely. It’s made of water-soluble materials that can be absorbed after a few weeks, eliminating the need for further surgery.

Just like an icepack, the cooling numbs the nerves, which slows down and eventually stops pain signals travelling to the brain.

The lab, led by biomedical engineering professor John A. Rogers, has previously developed a bioresorbable pacemaker and an implant that speeds up nerve regeneration.

He says of the latest invention: “As engineers, we are motivated by the idea of treating pain without drugs – in ways that can be turned on and off instantly, with user control over the intensity of relief. The technology reported here exploits mechanisms that have some similarities to those that cause your fingers to feel numb when cold. Our implant allows that effect to be produced in a programmable way, directly and locally to targeted nerves, even those deep within surrounding soft tissues.”

The real-time monitoring is crucial, he adds, to stop excessive cooling that could damage nerves and tissues.

At this stage it’s only in a rat model, though, so unfortunately we can’t tell you about the patients’ subjective experience.

We look forward to the first human trials of this very cool technology.

If something gives you the chills, pass it on to penny@medicalrepublic.com.au.