"The biosensor chip has tiny wires, about onefifth the diameter of a human hair, embedded in a circular pattern," says Eric Simone, a senior biomedical engineering student at Johns Hopkins University. "When it's connected to a power source, it lets us generate an electric field that can transport molecules to a designed area," he adds.

The chip takes advantage of the natural negative charge possessed by DNA or of a surface charge imposed on the molecules. A tiny drop of liquid containing the DNA is placed on top of the chip. The electric field guides the molecules to a designated area, where they can be analyzed under a microscope.