At the Institute for Basic Science in Daejeon, South Korea, scientists have developed a hydrogel that responds to the presence of nitric oxide (NO) and releases drugs when so activated. This kind of drug delivery system may be particularly effective for treating rheumatoid arthritis, as immune cells within inflamed joints release toxic NO in large quantities. Injecting a gel that actively responds to inflammation, absorbs NO, and immediately delivers anti-inflammatories or other drugs may allow for automatic long-term control of inflamed joints. The same applies to many other diseases and conditions involving inflammation.
The gel puffs up when nitric oxide is in its environment, but stays in its original shape no matter what other gas is present. As it puffs up and traps the toxic NO, it can be made to release drug molecules embedded within its volume. The amount of the release of the drug is effectively proportional to the intake of NO.
An announcement from the Institute for Basic Science explains some of the details:
NO is a transient gas, which stays in circulation for less than 10 seconds, before binding to other molecules. The research team developed a gel responsive to such fugitive molecules, using acrylamide as a base material and a new crosslinker to keep it in place. Unlike the monomeric form, polymeric acrylamide hydrogel has little toxicity and can contain a large amount of water. In addition, the cross-linking agent (NOCCL) forms bridges between the acrylamide molecules creating a net, which can trap drug molecules inside. When NO cleaves the NOCCL bridges, the gel changes its structure, frees the drug and absorbs new liquid.
Study in journal Advanced Materials: Therapeutic-Gas-Responsive Hydrogel…