One evening, Brigham & Women's Hospital nanoparticle specialist Jeffrey Karp met Harvard and Mass. General dermatologist R. Rox Anderson at a dinner and the two decided that they should work together to tackle medical problems. So, after dinner, Karp sat at his computer to figure out what they could do together and was distracted by his own hands, which were red and itchy because of his allergic reactions to nickel. Nickel is found in commonplace objects like jewelry, coins and cell phones. And Karp is not the only one with this problem. About 30 to 45 million people in the United States alone are allergic to nickel. So, a partnership was born. The researchers came up with a cream with nanoparticles containing calcium that could act as a barrier between invading nickel and the skin. Their research appears in the April 3 online edition of Nature Nanotechnology. Release