An innovative device warns of high levels of metals in the air

The researcher, Charles Henry, and his colleagues, explain that worldwide, respiratory diseases originating from workplaces cause almost half a million deaths every year

A group of scientists reports on the development of an innovative paper-based device capable of alerting workers that they are exposed to harmful levels of airborne metals almost immediately, compared to several weeks, the amount of time required for such testing in existing devices. The production cost of the new device is one cent and it will be able to prevent diseases among millions of people who work with metals.

The researcher, Charles Henry, and his colleagues, explain that worldwide, respiratory diseases originating from workplaces cause almost half a million deaths every year. Airborne metals are the main cause of these respiratory diseases. Millions of workers handle metals on a daily basis in the construction, manufacturing and transportation industries, and tiny amounts of these metals can become trapped in the air as a fine powder and enter the workers' bodies during breathing. Exposure to airborne metals has been linked to lung and liver cancer, respiratory diseases (shortness of breath, emphysema and bronchitis) and disorders of the immune system. Despite the seriousness of this issue, people have been using the same method to monitor metals for 25 years. This method is expensive and its tests take weeks. In order to overcome these challenges, the researchers developed a cheap device consisting of paper that produces the required results immediately. This innovative device provides workers with an opportunity to leave a hazardous area before it becomes too late.

The researchers take samples from the air and put them in a small paper disc. They then insert this chip into a paper-based device, known as a μPAD or micro-PAD. Water is poured on the board and then the metals in the sample penetrate the paper where they react with a number of different chemicals that are pre-soaked in it. These different materials react with the metals and an indication is obtained in the form of a color, where each color corresponds to a different metal. During laboratory experiments the device was able to accurately determine the correct amounts of the metals iron, nickel and copper found in the air.

Mallory M. Mentele; Josephine Cunningham; Kirsten Koehler; John Volckens; Charles S. Henry; Anal. Chem. 2012, 84, 4474-4480. DOI: 10.1021/ac300309c

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