Two groups of researchers have independently built the first biological analogue of the transistor - an integral element of modern electronics. It should make it easier to create gadgets out of living cells, such as biosensors that detect polluted water.
A transistor acts as a switch, converting electrical inputs into output signals via logic gates. Now, Drew Endy (pictured) at Stanford University in California and colleagues have designed a transistor-like device that controls the movement of an enzyme called RNA polymerase along a strand of DNA, just as electrical transistors control the flow of current through a circuit.
Source:
http://www.electronicsweekly.com/Articles/2013/04/03/55868/biological-transistors-switch-way-for-biosensors.htm
