Researchers at Harvard’s Whitesides Research Group have built a microfluidic “lab-on-a-chip” made out of paper.

They are developing it for disposable diagnostic tests that could be used anywhere in the world. The researchers plan to combine the paper tests with a system of cell phones for off-site diagnosis.

A hydrophobic polymer added to the paper guides liquids along prescribed channels and seals off unwanted channels. Natural capillary action avoids the need for external pumps or power.

Existing microfluidic chips are generally made from comparatively expensive materials like silicon, glass, or plastic and have tiny pumps and valves that can be difficult to manufacture.