Nanotech: A Billion Computers In a Drop of Water

The development of the first 'programmable, two-state, two-symbol, finite automaton' could have enormous consequences.







Scientists at Israel's Weizmann Institute of Science, using DNA molecules, have created the world's first programmable biological computer -- so small that a billion of them can fit in a single drop of water.
These extraordinarily tiny machines are capable of performing billions of simple mathematical operations per second with a 99.8 percent degree of accuracy -- while using less than one billionth of a watt of power.

There is some question over whether or not the machines technically constitute "computers" -- and even if they do, they are extremely rudimentary. But the achievement is a major step toward a future in which computers can be worn on -- or even inside -- the human body.

"For instance, such a future computer could sense an abnormal biochemical change in the body and decide how to correct it by synthesizing and releasing the necessary drug," said Zvi Livneh, the Institute's resident DNA expert.

'Programmable Automatons'

Biological computers have been possible in theory for a long time in the field of nanotechnology, the study of incredibly small things that compute. The development by the Israelis of the first "programmable, two-state, two-symbol, finite automaton," even if it is not a computer in the sense we normally think of one, could have enormous consequences.

"It is a computer, but not a general purpose, universal computer," Ehud Shapiro, director of the research team at the Institute, told NewsFactor Network.

"What we implemented is the simplest possible nontrivial, finite automaton, which has only two states and an alphabet of two symbols. It can answer only simple questions," Shapiro said.

The first simple question the bio-computer solved was to determine whether or not a list of 0s and 1s had an even number of 1s. Since then, scientists at the Institute have created a total of 765 "software programs."

DNA's Limitless Potential

Though they are simple, the bio-computers can perform certain functions very quickly. For example, scientists said they might be able to speed up the time-consuming study of DNA by forming the basis of computers capable of screening DNA libraries in parallel, without sequencing each molecule as is required now.

DNA has vast memory capacity -- the trick is to exploit its nearly limitless potential.

"The living cell contains incredible molecular machines that manipulate information-encoding molecules such as DNA and RNA in ways that are fundamentally very similar to computation," Shapiro said.

"Since we don't know how to effectively modify these machines or create new ones just yet, the trick is to find naturally existing machines that, when combined, can be steered to actually compute," he added.

Molecular-Level Treatment

The bio-computer uses two naturally occurring enzymes that can manipulate DNA as its "hardware." The "software" and "hardware" molecules, when mixed in a solution, operate in harmony on what is known as the "input" molecule. What results is a simple mathematical computing machine known as a "finite automaton."

It then can be programmed to perform simple tasks by choosing different "software" molecules to be mixed in solution.

"Such machines might analyze natural DNA, human or otherwise, in the lab within a few years," Shapiro said. "The time when such machines can actually operate within the human body, programmed with medical knowledge so that they can effect some medical treatment at the molecular level, is at least a few decades away."