Part of the show How age affects DNA and How the Body Clock Works
Scientists at the University of Strathclyde have developed an oxygen-sensitive ink that to warn you that food packaging is leaky. Food is normally packaged in a protective oxygen-free atmosphere containing nitrogen or carbon dioxide which helps to keep the food fresh. The new ink, which is colourless, turns blue when it comes into contact with oxygen. So a blue spot on the inside of the food packaging would alert you that the packet is leaky. The new ink consists of a dye called methylene blue, and nanoparticles of titanium dioxide. When the dye is activated with ultraviolet light it becomes colourless, but when it comes into contact with oxygen, it goes blue again.