Researchers at the University of Cambridge have developed a new material that could improve the treatment of arthritis by releasing drugs directly at inflamed joints. The material is designed to sense small changes in acidity, which occur during an arthritis flare-up, and respond by becoming softer and releasing encapsulated anti-inflammatory drugs.
The research team says this approach allows for precise drug delivery, as the material only reacts within a narrow pH range typical of inflamed tissue. This could reduce side effects by ensuring medication is released only where needed. Arthritis affects more than 10 million people in the UK and costs the NHS about £10.2 billion each year. Globally, over 600 million people are affected by the condition.
The new material uses engineered reversible crosslinks within a polymer network, making it highly responsive to changes in acidity levels. It was developed in Professor Oren Scherman’s group at Cambridge’s Yusuf Hamied Department of Chemistry.
“For a while now, we’ve been interested in using these materials in joints, since their properties can mimic those of cartilage,” said Scherman, who is Professor of Supramolecular and Polymer Chemistry and Director of the Melville Laboratory for Polymer Synthesis. “But to combine that with highly targeted drug delivery is a really exciting prospect.”
“These materials can ‘sense’ when something is wrong in the body and respond by delivering treatment right where it’s needed,” said first author Dr Stephen O’Neill. “This could reduce the need for repeated doses of drugs, while improving patient quality of life.”
Unlike other drug delivery systems that require external triggers such as heat or light, this system relies on natural chemical changes within the body. In laboratory tests using a fluorescent dye to simulate drug behavior, researchers observed increased release at acidity levels typical of arthritic joints compared to healthy tissue.
“By tuning the chemistry of these gels, we can make them highly sensitive to the subtle shifts in acidity that occur in inflamed tissue,” said co-author Dr Jade McCune. “That means drugs are released when and where they are needed most.”
The researchers believe their method could be adapted for other medical conditions by adjusting the chemistry of the material. “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.
Next steps include testing the material in living systems to assess its safety and effectiveness. The research received support from the European Research Council and UK Research and Innovation's Engineering and Physical Sciences Research Council (EPSRC). Commercialisation efforts are underway with Cambridge Enterprise.