Paper lab-on-a-chip marked with an image of Africa. Dropper applying coloured solution to a paper microfluidic device, also known as a lab-on-a-chip. This device is formed from several layers of paper that have been treated with a water-resistant polymer except untreated channels drawn into the shape of Africa. The natural soaking action of the untreated paper allows fluid to flow along the channels into wells coated with proteins or antibodies. Paper lab-on-a-chips could one day offer a cheap, disposable device to diagnose diseases and detect contaminants in water. Photographed in 2009 at the Whitesides Research Group, Harvard University, USA.