Paper lab-on-a-chip. Dropper applying coloured solution on to paper microfluidic devices, also known as the lab-on-a-chip. This device is formed from several layers of paper that have been treated with a water-resistant polymer except channelled areas which are left untreated. The natural soaking action of the untreated paper allows fluid to flow along the channels into wells coated with proteins or antibodies.The paper lab-on-a-chip 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.