Experimental Implant Could Dispense Drugs Inside Joints During Arthritis Flares

By Crystal Lindell

Researchers in the UK are developing an artificial cartilage that could dispense anti-inflammatory and pain relieving medications from within joints during an arthritis flare-up.

The gel-like material, developed by a team at the University of Cambridge, has been designed to respond to changes in pH, a measure of acidity. During flare-ups, arthritic joints become inflamed and slightly more acidic than the surrounding tissue.

As acidity increases, the polymer implant becomes softer and more jelly-like, triggering the release of drug molecules within the joint. In theory, researchers say the drugs would be released precisely where and when they are needed, providing more effective and continuous relief.

“These materials can ‘sense’ when something is wrong in the body and respond by delivering treatment right where it’s needed,” said Stephen O’Neill, PhD, a postdoctoral researcher at Cambridge. “This could reduce the need for repeated doses of drugs, while improving patient quality of life.”

The research was reported in the Journal of the American Chemical Society. 

The polymer material was developed by a research group in the Department of Chemistry at Cambridge that specializes in designing and building unique materials for a range of potential applications.

“For a while now, we’ve been interested in using these materials in joints, since their properties can mimic those of cartilage,” said lead author Oren Scherman, PhD, Director of the Melville Laboratory for Polymer Synthesis. “But to combine that with highly targeted drug delivery is a really exciting prospect.”

Clinical trials are needed before the material can be used in patients. Researchers say their next steps will be to test the materials in living organisms to evaluate their performance and safety. 

If successful, that could lead to a new generation of responsive biomaterials capable of treating a variety of chronic diseases. The gel could be adapted for placement in different parts of the body.

“It’s a highly flexible approach, so we could in theory incorporate both fast-acting and slow-acting drugs, and have a single treatment that lasts for days, weeks or even months,” said O’Neill.

While it is incredible to see these new advances in pain treatment, it’s also imperative that researchers make sure that they are actually better than the current treatments available. They also need to make sure that the implants are relatively easy to remove in the case of complications.

In the research paper, the authors suggest the implants could be used for rheumatoid and osteoarthritis pain. However, both of those diseases can cause widespread joint pain, so it remains unclear if material needs to be implanted in multiple joints to be effective.

And if the implants can be effective “for days, weeks or even months,” how would they be re-loaded with medication or even fully replaced? Such a process could be very taxing for patients, especially if it requires a trip to the hospital or a doctor’s office each time.

In the original Jurassic Park movie, the character Dr. Ian Malcolm says, “Your scientists were so preoccupied with whether they could, they didn't stop to think if they should.”

I hope these researchers heed that advice. 

Tiny Electrode Could Expand Use of Spinal Cord Stimulators

By Pat Anson, PNN Editor

A tiny inflatable device – about the width of a human hair – could make spinal cord stimulation less invasive and more practical for millions of people who suffer from chronic back or leg pain, according to researchers at the University of Cambridge.

Long considered the treatment of last resort, spinal cord stimulators (SCSs) are bulky devices implanted along the spine that use electrode wires connected to a battery to emit electric currents that block pain signals from reaching the brain. About 50,000 stimulators are surgically implanted every year, but many wind up being removed due to complications from surgery or because they are ineffective.

“Our goal was to make something that’s the best of both worlds – a device that’s clinically effective but that doesn’t require complex and risky surgery,” said Christopher Proctor, PhD, a research fellow at Cambridge’s Department of Engineering and one of the senior authors of a study published in Science Advances. “This could help bring this life-changing treatment option to many more people.”

Proctor and his colleagues developed a miniaturized electrode that is so small it can be rolled up into a tiny cylinder, inserted into a needle, and implanted into the epidural space of the spinal column.

As the video below shows, the device can then be inflated with water or air so that it unrolls like a tiny air mattress and covers part of the spine. When connected to a battery, the ultra-thin electrode can send small electric currents to the spinal cord, just like a traditional stimulator.

“In order to end up with something that can be implanted with a needle, we needed to make the device as thin as possible,” said co-author Ben Woodington, a PhD candidate in Cambridge’s Department of Engineering.

Researchers made the device with flexible electronics used in the semiconductor industry; tiny fluidic channels used in drug delivery; and shape-changing materials used in robotics.

“Thin-film electronics aren’t new, but incorporating fluid chambers is what makes our device unique – this allows it to be inflated into a paddle-type shape once it is inside the patient,” said Proctor.  

Early versions of the device were so thin they were invisible to x-rays, which surgeons would need to confirm the device was in the right place before inflating it. Researchers added some bismuth particles to make the device visible without increasing the thickness too much.

The experimental device has only been tested in human cadavers. More extensive testing and clinical trials will be required before the device can be used on patients – possibly in two or three years. The Cambridge research team is currently working with a manufacturer to further develop and improve the device.

“The way we make the device means that we can also incorporate additional components – we could add more electrodes or make it bigger in order to cover larger areas of the spine with increased accuracy,” said senior co-author Damiano Barone, MD, a clinical lecturer in Cambridge’s Department of Clinical Neurosciences.

“This adaptability could make our SCS device a potential treatment for paralysis following spinal cord injury or stroke or movement disorders such as Parkinson’s disease. An effective device that doesn’t require invasive surgery could bring relief to so many people.”

“This technology has the potential to transform clinical treatment, significantly improve pain management for so many people, and reach patients who cannot be treated with existing devices,” said Rachel Atfield, PhD, Commercialisation Manager at Cambridge Enterprise, which has patented the device.

A 2018 study by a team of investigative journalists found that spinal cord stimulators have some of the worst safety records of medical devices tracked by the U.S. Food and Drug Administration. A review of FDA data found over 500 deaths and 80,000 injuries involving stimulators since 2008. Patients reported being shocked or burned by the devices and many had them removed.