Doctors could soon be using them in implants to control the release of...
Doctors could soon be using them in implants to control the release of painkillers within tissue.
Source: 2019 EPFL/ Murielle Gerber

Circuit implants release painkillers inside the body

Researchers have developed biodegradable microresonators that could soon be used in implants to control the release of painkillers within tissue.

Patients fitted with an orthopedic prosthetic commonly experience a period of intense pain after surgery. In an effort to control the pain, surgeons inject painkillers into the tissue during the operation. When that wears off a day or two later, the patients are given morphine through a catheter placed near the spine. Yet catheters are not particularly comfortable, and the drugs spread throughout the body, affecting all organs.

Researchers in EPFL’s Microsystems Laboratory at the School of Engineering are now working on a biodegradable implant that would release a local anesthetic on-demand over several days. Not only would this implant reduce patients’ post-op discomfort, but there would be no need for further surgery to remove it. They developed a tiny biodegradable electronic circuit, made from magnesium, that could be heated wirelessly from outside the body.

Once integrated into the final device, the circuit will allow to release controlled amounts of anesthetic in a specific location over several days. After that, the implant will degrade safely inside the body.

One capsule with several reservoirs

Photo

The electronic circuit – a resonant circuit in the shape of a small spiral – is just a few microns thick. When exposed to an alternating electromagnetic field, the spiral resonator produces an electric current that creates heat.

The researchers’ end-goal is to pair the resonators with painkiller-filled capsules and then insert them into the tissue during surgery. The contents of the capsules could be released when an electromagnetic field sent from outside the body melts the capsule membrane. “We’re at a key stage in our project, because we can now fabricate resonators that work at different wavelengths,” says Matthieu Rüegg, a PhD student and the study’s lead author. “That means we could release the contents of the capsules individually by selecting different frequencies.” The heat-and-release process should take less than a second.

The researchers had to get creative when it came time to manufacture their biodegradable resonators. “We immediately ruled out any fabrication process that involved contact with water, since magnesium dissolves in just a few seconds,” says Rüegg. They ended up shaping the magnesium by depositing it on a substrate and then showering it with ions. “That gave us more flexibility in the design stage,” he adds. They were eventually able to create some of the smallest magnesium resonators in the world: two microns thick, with a diameter of three millimeters.

The team’s invention is not quite ready for the operating room. “We still need to work on integrating the resonators into the final device and show that it’s possible to release drugs both in vitro and in vivo,” concludes Rüegg.

Subscribe to our newsletter

Related articles

Prosthetics: sensors implanted for wireless control of muscle signal

Prosthetics: sensors implanted for wireless control of muscle signal

Researchers have successfully implanted sensors in three male patients following nerve transfers, to transmit biosignals for wireless control of robotic arms.

Integrate micro chips for electronic skin

Integrate micro chips for electronic skin

First fully integrated flexible electronics made of magnetic sensors and organic circuits opens the path towards the development of electronic skin.

Bioelectronic implant could prevent opioid deaths

Bioelectronic implant could prevent opioid deaths

Researchers are developing a device that can sense the effects of a potentially fatal level of ingested opioids and deliver a life-saving dose of naloxone.

First sentient hand prosthesis implanted

First sentient hand prosthesis implanted

A female Swedish patient with hand amputation has become the first recipient of an osseo-neuromuscular implant to control a dexterous hand prosthesis.

Are smart knee implants the future of joint replacements?

Are smart knee implants the future of joint replacements?

Researchers decided it was time to create smarter knee implants that could monitor changes in activity as they happened.

Regrowing long bone segments using 3D printing

Regrowing long bone segments using 3D printing

Not all broken bones heal. But one scientist at the University of Arizona hopes to remedy that problem using a combination of 3D printing and adult stem cells.

Nerve-on-a-chip improves neuroprosthetics

Nerve-on-a-chip improves neuroprosthetics

Scientists have developed a miniaturized electronic platform for the stimulation and recording of peripheral nerve fibers-on-a-chip.

Bringing the bling to improve implants

Bringing the bling to improve implants

Researchers have for the first time successfully coated 3D printed titanium implants with diamond.

3D printed artery monitors blockages from the inside

3D printed artery monitors blockages from the inside

Engineers are developing a 3D printed artificial blood vessel that allows doctors and patients to keep tabs on its health remotely.

Popular articles