All patients operated on for an orthopedic prosthesis typically experience a post-operative period of intense pain.
To help control it, surgeons usually directly inject painkillers into the tissues during the operation. When the effect wears off, two or three days later, patients receive morphine through a small catheter placed behind the spine. A not very comfortable solution, and moreover the painkillers in this way do not only act where they are needed, but on all the organs.
A research team at the EPFL laboratories (Polytechnic of Lausanne, Switzerland) works on biodegradable circuits capable of administering a local anesthetic on request for several days. Not only does this device reduce post-operative discomfort, it does not require interventions for subsequent removal.
What is it about
The implant consists of a thin, biodegradable electrical circuit, made of magnesium, that can be heated remotely from outside the body.
Once integrated into the final device, the circuit allows you to release controlled doses of anesthetic in specific points of the body for several days.
When it has fulfilled its task, the implant dissolves in a totally non-toxic way in the body.
The study was published in the latest issue of the scientific journal Advanced Functional Materials.
One capsule, many doses
The small circuit that forms the basis of the system (a resonant circuit with a tiny spiral shape) is often only a few microns. When exposed to an alternating electromagnetic field, the resonator circuit produces an electric current that creates heat.
The ultimate goal is to equip the biodegradable circuits with small painkiller capsules and insert them into the body during surgery. The contents of the capsules will be distributed upon request.
The state of research
“We are at a key point: we can now make resonators that work at different wavelengths,” says Matthieu Rüegg, author of the study. “This will allow us to release several capsules over time, each for each frequency.” The release process takes place in less than a second.
A new production technique
The researchers used all their creativity when it came to building biodegradable resonators. “We immediately discarded any manufacturing process that involved the use of water, as the magnesium would dissolve within seconds. They ended up forming magnesium by depositing it on a framework and spraying it with ions.
"This gave us more flexibility in the design phase. Today we are able to create the smallest magnesium resonator in the world: 3 millimeters in diameter and two microns thick."
The team is not yet ready to give its invention to the operating rooms. “We need to work on resonators and show that the release of painkillers is as possible live as in vitro”he concludes Rüegg.
