Counterfeit drugs reportedly kill more than 700,000 people annually, and there have been reports of a rise in bogus medical devices, as well. To combat this alarming trend, researchers at the University of Michigan and in South Korea have developed a technique that reveals a hidden image in labels when they are breathed on, allowing users to authenticate a product.
The method involves the creation of tiny features, called nanopillars, that are approximately 500 times smaller than the width of a human hair. The nanopillar array on the surface of a label, which can be plastic, fabric, paper, or metal, hides a text or image. Condensation produced by breathing on the material reveals the underlying graphic.