Researchers at the Weizmann Institute of Science have built a tiny computing machine in a test tube using biological molecules. The programmable computer is so small that a trillion such computers can co-exist and compute in a drop of water at room temperature. The bio-computer can perform a billion operations per second with greater than 99.8% accuracy, and requires less than a billionth of a watt of power. Though the project is not at the application stage, it may lead to future computers that can operate within the human body. “For instance, such a computer in the future could sense an abnormal biochemical change in the body and decide how to correct it by synthesizing and releasing the necessary drug,” says Prof. Tzvi Livneh, a DNA expert from the Institute\'s Department of Biological Chemistry who took part in the project.



The computer\'s input, output and software are made up of DNA molecules, while two naturally-occurring enzymes that manipulate DNA serve as hardware. The software and hardware molecules operate in harmony on the input molecule to create the output molecule, forming a simple mathematical computing machine, known as a finite automaton. The nano-computer can be programmed to perform several simple tasks by choosing different software molecules to be mixed in solution.