Nickel allergy fought more efficiently by calcium nanoparticles
Nanoparticles could offer big hope in a small package to the many millions of people who are allergic to the nickel in everything from jewelry to coins and cell phones. The allergy causes a red, itchy rash when it comes into contact with their skin. Although some countries regulate the amount of the metal in certain products to limit exposure, there was no solution to the problem.
“There have been approaches to developing creams with agents that bind the nickel before it can penetrate the skin, but these are not effective in most patients and can even be toxic when the agents themselves penetrate the skin, as most do”, said Jeffrey Karp, leader of the research and co-director of the Center for Regenerative Therapeutics at Brigham and Women’s Hospital. “People also sometimes coat their jewelry with nail polish to create a barrier between the skin and nickel ions, but this won’t prevent all exposures, such as handling coins or wearing a watch.”
Karp and colleagues including R. Rox Anderson, a dermatologist at Harvard Medical School and Massachusetts General Hospital, have found that nanoparticles containing calcium could offer a safe solution to the problem. The team began by focusing on compounds containing calcium, which are known to sequester nickel (some are used in the treatment of water). Next, they explored whether these compounds were available as nanoparticles. Karp knew that the tiny particles could potentially allow very efficient nickel capture thanks to their very high surface area.
They decided to use particles with diameter between 70 and 500 nanometers. In order to cut the time involved in bringing a new technology to market, the team only explored nanoparticles already designated by the Food and Drug Administration as being generally recognized as safe. They found two compounds that met these criteria (calcium carbonate and calcium phosphate), added them to a common emollient to create a cream, and tested them under a variety of experimental conditions.
When applied to the skin in a cream form, the nanoparticles efficiently capture the nickel, preventing it from making its way into the body. Further, the nanoparticles themselves were designed so that they cannot penetrate the skin. The cream with its nickel can then be easily washed off with water. Compared to existing nickel-capture agents, this approach needs 11-fold fewer nanoparticles to achieve the same effect.
For more information you can read the article published in the Nature Nanotechnology named: “Nanoparticles reduce nickel allergy by capturing metal ions”.