Nanosensors being developed by California Institute of Technology researchers will simultaneously look for thousands of different biomolecules and could be the basis for more accurate, cheaper, and more convenient cancer tests.

To turn a nanowire into a transistor, the researchers bring each of its ends into contact with metal wires so that a current can be passed through it. They then position an electrode close to the nanowire. Charging this electrode alters the conductivity of the nanowire, turning it “on” and “off.”

They then transform the nanowire transistors into tiny biosensors that can act as sensors for particular proteins. The researchers coat the surface of the wire with antibodies that will stick to the target protein but not to other molecules. When proteins bind to the antibodies, they interact with the electrons traveling in the nanowire’s surface layer, altering its conductivity.